v3.20.1
Financial Instruments and Fair Value Measures - Bases Used To Measure The Approximate Fair Values Of Financial Instruments (Details) - USD ($)
$ in Millions
Mar. 31, 2020
Dec. 31, 2019
Liabilities    
Carrying amount of investments in equity securities that do not have readily determinable fair values $ 75 $ 66
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 3,750 3,753
Long-term debt and finance lease obligations, excluding fair value hedges 66,157 66,631
Total liabilities 69,907 70,384
Book value    
Liabilities    
Short-term Debt, Fair Value 6  
Current portion of long-term debt and finance lease obligations, excluding fair value hedges 3,756 3,755
Long-term debt and finance lease obligations, excluding fair value hedges 62,974 63,021
Total liabilities 66,736 66,776
Approximate fair value    
Liabilities    
Short-term Debt, Fair Value 6  
Current portion of long-term debt and finance lease obligations, excluding fair value hedges 3,757 3,760
Long-term debt and finance lease obligations, excluding fair value hedges 66,176 66,651
Total liabilities 69,939 70,411
Approximate fair value | Quoted prices in active markets for identical assets (Level 1)    
Liabilities    
Short-term Debt, Fair Value 0  
Approximate fair value | Significant other observable inputs (Level 2)    
Liabilities    
Short-term Debt, Fair Value 6  
Current portion of long-term debt and finance lease obligations, excluding fair value hedges 7 7
Long-term debt and finance lease obligations, excluding fair value hedges 19 20
Total liabilities 32 27
Approximate fair value | Significant unobservable inputs (Level 3)    
Liabilities    
Short-term Debt, Fair Value 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