v3.20.4
Debt - 2020 Financing Activities (Details) - USD ($)
Dec. 31, 2020
Sep. 28, 2020
May 01, 2020
Dec. 31, 2019
Nov. 30, 2014
Debt Instrument [Line Items]          
Debt instrument, principal amount $ 7,650,000,000     $ 7,400,000,000  
Unsecured Debt | Fixed-rate 2.7% senior unsecured notes          
Debt Instrument [Line Items]          
Debt instrument, principal amount 500,000,000   $ 500,000,000 0  
Range of interest rates     2.70%    
Unsecured Debt | Fixed-rate 3.15% senior unsecured notes          
Debt Instrument [Line Items]          
Debt instrument, principal amount 500,000,000   $ 500,000,000 0  
Range of interest rates     3.15%    
Unsecured Debt | Fixed-rate 3.4% senior unsecured notes          
Debt Instrument [Line Items]          
Debt instrument, principal amount 1,000,000,000   $ 1,000,000,000 0  
Range of interest rates     3.40%    
Unsecured Debt | Fixed-rate 4.125% senior unsecured notes          
Debt Instrument [Line Items]          
Debt instrument, principal amount 0     1,350,000,000  
Range of interest rates   4.125%      
Debt redeemed   $ 1,350,000,000      
Unsecured Debt | Fixed-rate 4.625% senior unsecured notes          
Debt Instrument [Line Items]          
Debt instrument, principal amount $ 0     $ 400,000,000  
Range of interest rates   4.625%      
Debt redeemed   $ 400,000,000      
Two Thousand Nineteen Cash Convertible Senior Notes [Member]          
Debt Instrument [Line Items]          
Debt instrument, principal amount         $ 1,150,000,000