| Net income | 
        | 
        | 
        | 
      1,528 | 
        | 
      1,669 | 
    
    
      | Income tax expense | 
        | 
      6.1 
		 | 
        | 
      271 | 
        | 
      55 | 
    
    
      | Result of equity-accounted investees | 
        | 
      5.3 
		 | 
        | 
      (4) | 
        | 
      28 | 
    
    
      | Financial income | 
        | 
      2.4 
		 | 
        | 
      (41) | 
        | 
      (33) | 
    
    
      | Financial expense | 
        | 
      2.4 
		 | 
        | 
      193 | 
        | 
      191 | 
    
    
      | Depreciation and amortisation of property, plant and equipment and intangible assets | 
        | 
      3.2, 3.3 
		 | 
        | 
      2,149 | 
        | 
      2,166 | 
    
    
      | Depreciation of right-of-use assets | 
        | 
      2.3 
		 | 
        | 
      286 | 
        | 
      282 | 
    
    
      | Gain on sale of property, plant and equipment | 
        | 
      1.2 
		 | 
        | 
      (10) | 
        | 
      (13) | 
    
    
      | Expense for share-based payments | 
        | 
        | 
        | 
      1 | 
        | 
      1 | 
    
    
      | Revenue from finance lease | 
        | 
        | 
        | 
      (101) | 
        | 
      (101) | 
    
    
      | Change in deferred gain from the sale and leaseback of real estate | 
        | 
      2.3 
		 | 
        | 
      (16) | 
        | 
      (12) | 
    
    
      | Change in operating assets and liabilities | 
        | 
      3.1 
		 | 
        | 
      178 | 
        | 
      112 | 
    
    
      | Change in provisions | 
        | 
      3.5 
		 | 
        | 
      (22) | 
        | 
      46 | 
    
    
      | Change in defined benefit obligations | 
        | 
      4.3 
		 | 
        | 
      65 | 
        | 
      48 | 
    
    
      | Interest received | 
        | 
        | 
        | 
      24 | 
        | 
      25 | 
    
    
      | Dividends received | 
        | 
      5.3 
		 | 
        | 
      15 | 
        | 
      18 | 
    
    
      | Interest payments on financial liabilities | 
        | 
      2.2 
		 | 
        | 
      (93) | 
        | 
      (88) | 
    
    
      | Interest payments on lease liabilities | 
        | 
      2.3 
		 | 
        | 
      (45) | 
        | 
      (42) | 
    
    
      | Income taxes paid | 
        | 
      6.1 
		 | 
        | 
      (309) | 
        | 
      (371) | 
    
    
      | Cash flow from operating activities | 
        | 
        | 
        | 
      4,069 | 
        | 
      3,981 | 
    
    
      | Purchase of property, plant and equipment and intangible assets | 
        | 
      3.2, 3.3 
		 | 
        | 
      (2,188) | 
        | 
      (2,390) | 
    
    
      | Sale of property, plant and equipment and intangible assets | 
        | 
        | 
        | 
      16 | 
        | 
      31 | 
    
    
      | Acquisition of subsidiaries, net of cash and cash equivalents acquired | 
        | 
      5.2 
		 | 
        | 
      (39) | 
        | 
      (394) | 
    
    
      | Sale of subsidiaries net of cash and cash equivalents sold | 
        | 
      5.2 
		 | 
        | 
      – | 
        | 
      (3) | 
    
    
      | Payments for equity-accounted investees | 
        | 
      5.2 
		 | 
        | 
      (15) | 
        | 
      (15) | 
    
    
      | Proceeds from finance lease receivables | 
        | 
        | 
        | 
      100 | 
        | 
      38 | 
    
    
      | Purchase of other financial assets | 
        | 
        | 
        | 
      (121) | 
        | 
      (13) | 
    
    
      | Proceeds from other financial assets | 
        | 
        | 
        | 
      20 | 
        | 
      52 | 
    
    
      | Remaining cash flows from investing activities | 
        | 
        | 
        | 
      (4) | 
        | 
      (39) | 
    
    
      | Cash flow used in investing activities | 
        | 
        | 
        | 
      (2,231) | 
        | 
      (2,733) | 
    
    
      | Issuance of financial liabilities | 
        | 
      2.2 
		 | 
        | 
      732 | 
        | 
      417 | 
    
    
      | Repayment of financial liabilities | 
        | 
      2.2 
		 | 
        | 
      (1,110) | 
        | 
      (374) | 
    
    
      | Repayment of lease liabilities | 
        | 
      2.3 
		 | 
        | 
      (287) | 
        | 
      (276) | 
    
    
      | Dividends paid to equity holders of Swisscom Ltd | 
        | 
      2.1 
		 | 
        | 
      (1,140) | 
        | 
      (1,140) | 
    
    
      | Dividends paid to non-controlling interests | 
        | 
        | 
        | 
      (1) | 
        | 
      (1) | 
    
    
      | Acquisition of non-controlling interests | 
        | 
        | 
        | 
      (1) | 
        | 
      (1) | 
    
    
      | Other cash flows from financing activities | 
        | 
        | 
        | 
      (17) | 
        | 
      (15) | 
    
    
      | Cash flow used in financing activities | 
        | 
        | 
        | 
      (1,824) | 
        | 
      (1,390) | 
    
    
      | Net increase (decrease) in cash and cash equivalents | 
        | 
        | 
        | 
      14 | 
        | 
      (142) | 
    
    
      | Cash and cash equivalents at 1 January | 
        | 
        | 
        | 
      328 | 
        | 
      474 | 
    
    
      | Foreign currency translation adjustments in respect of cash and cash equivalents | 
        | 
        | 
        | 
      (2) | 
        | 
      (4) | 
    
    
      | Cash and cash equivalents at 31 December | 
        | 
        | 
        | 
      340 | 
        | 
      328 |