v3.21.1
Financial Instruments and Fair Value Measures - Bases Used To Measure The Approximate Fair Values Of Financial Instruments (Details) - USD ($)
$ in Millions
Mar. 31, 2021
Dec. 31, 2020
Liabilities    
Carrying amount of investments in equity securities that do not have readily determinable fair values $ 110 $ 102
Quoted prices in active markets for identical assets (Level 1)    
Liabilities    
Current portion of long-term debt and finance lease obligations, excluding fair value hedges 10,862 8,249
Long-term debt and finance lease obligations, excluding fair value hedges 78,975 86,137
Total liabilities 89,837 94,386
Book value    
Liabilities    
Short-term borrowings 9 34
Current portion of long-term debt and finance lease obligations, excluding fair value hedges 11,331 8,461
Long-term debt and finance lease obligations, excluding fair value hedges 73,981 77,283
Total liabilities 85,321 85,778
Approximate fair value    
Liabilities    
Short-term borrowings 9 34
Current portion of long-term debt and finance lease obligations, excluding fair value hedges 11,400 8,542
Long-term debt and finance lease obligations, excluding fair value hedges 80,280 87,761
Total liabilities 91,689 96,337
Approximate fair value | Quoted prices in active markets for identical assets (Level 1)    
Liabilities    
Short-term borrowings 0 0
Approximate fair value | Significant other observable inputs (Level 2)    
Liabilities    
Short-term borrowings 9 34
Current portion of long-term debt and finance lease obligations, excluding fair value hedges 538 293
Long-term debt and finance lease obligations, excluding fair value hedges 1,305 1,624
Total liabilities 1,852 1,951
Approximate fair value | Significant unobservable inputs (Level 3)    
Liabilities    
Short-term borrowings 0 0
Current portion of long-term debt and finance lease obligations, excluding fair value hedges 0 0
Long-term debt and finance lease obligations, excluding fair value hedges 0 0
Total liabilities $ 0 $ 0