v3.20.4
Financial Instruments - Long-Term Debt (Details) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Debt Instrument [Line Items]    
Net fair value adjustments related to hedging and purchase accounting $ 0 $ 5
Net unamortized discounts, premiums and debt issuance costs (2) (43)
Total long-term debt, carried at historical proceeds, as adjusted 37,133 35,955
Current portion of long-term debt, carried at historical proceeds, as adjusted (not included above (2.6% and 1.2%)) $ 2,002 $ 1,462
Unsecured Debt [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 2.60% 1.20%
Total principal amount of long-term debt $ 35,774 $ 34,820
Net fair value adjustments related to hedging and purchase accounting 1,562 1,305
Net unamortized discounts, premiums and debt issuance costs (207) (176)
Other long-term debt 4 5
Total long-term debt, carried at historical proceeds, as adjusted 37,133 35,955
Current portion of long-term debt, carried at historical proceeds, as adjusted (not included above (2.6% and 1.2%)) 2,002 $ 1,462
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2021 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage   2.40%
Total principal amount of long-term debt [1] $ 0 $ 3,153
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2022 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 1.00% 1.00%
Total principal amount of long-term debt $ 1,728 $ 1,624
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2023 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 3.20% 3.70%
Total principal amount of long-term debt $ 2,550 $ 2,892
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2024 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 3.90% 3.90%
Total principal amount of long-term debt $ 2,250 $ 2,250
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2025 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 0.80%  
Total principal amount of long-term debt $ 750 $ 0
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2026 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 2.90% 2.90%
Total principal amount of long-term debt $ 3,000 $ 3,000
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2027-2030 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 3.10% 3.60%
Total principal amount of long-term debt $ 6,781 $ 4,453
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2034-2036 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 5.30% 5.30%
Total principal amount of long-term debt $ 2,250 $ 2,250
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2037-2040 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 5.60% 6.00%
Total principal amount of long-term debt $ 8,086 $ 7,066
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2043-2046 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 3.70% 3.70%
Total principal amount of long-term debt $ 4,878 $ 4,818
Unsecured Debt [Member] | Senior Unsecured Debt, Due 2047-2050 [Member]    
Debt Instrument [Line Items]    
Interest rate, percentage 3.60% 4.10%
Total principal amount of long-term debt $ 3,500 $ 3,315
[1] Reclassified to the current portion of long-term debt.