v3.10.0.1
Financial Instruments - Investments (Details) - USD ($)
$ in Millions
Dec. 31, 2018
Dec. 31, 2017
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]    
Debt securities, amortized cost $ 16,920 $ 22,337
Debt securities, gross unrealized gains 8 77
Debt securities, gross unrealized losses (85) (100)
Debt securities maturities, within 1 year, fair value 16,293  
Debt securities maturities, over 1 to 5 years, fair value 512  
Debt securities maturities, over 5 years, fair value 38  
Debt Securities, Available-for-sale and Held-to-maturity 16,842 22,313
Available-for-sale Equity Securities [Abstract]    
Available-for-sale equity securities, amortized cost [1]   2,843
Available-for-sale equity securities, gross unrealized gain [1]   586
Available-for-sale equity securities, gross unrealized losses [1]   (124)
Available-for-sale securities, equity securities [1]   3,304
Government and agency debt - non-U.S. [Member]    
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]    
Available-for-sale debt securities, amortized cost 9,754 12,616
Available-for-sale debt securities, gross unrealized gain 7 61
Available-for-sale debt securities, gross unrealized loss (58) (48)
Available-for-sale securities, debt maturities 9,703 12,629
Available-for-sale Securities, Debt Maturities [Abstract]    
Available-for-sale securities, debt maturities, within 1 year, fair value 9,609  
Available-for-sale securities, debt maturities, over 1 to 5 years, fair value 94  
Available-for-sale securities, debt maturities, over 5 years, fair value 0  
Available-for-sale securities, debt maturities 9,703 12,629
Debt Securities, Held-to-maturity, Maturity [Abstract]    
Held-to-maturity securities, debt maturities, total 592 770
Held-to-maturity securities, gross unrealized gains 0 0
Held-to-maturity securities, gross unrealized losses 0 0
Held-to-maturity securities, fair value 592 770
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]    
Held-to-maturity securities, debt maturities, within 1 year, fair value 592  
Held-to-maturity securities, debt maturities, over 1 to 5 years, fair value 0  
Held-to-maturity securities, debt maturities, over 5 years, fair value 0  
Corporate and Other [Member]    
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]    
Available-for-sale debt securities, amortized cost [2] 5,905 7,859
Available-for-sale debt securities, gross unrealized gain [2] 0 15
Available-for-sale debt securities, gross unrealized loss [2] (27) (52)
Available-for-sale securities, debt maturities [2] 5,878 7,823
Available-for-sale Securities, Debt Maturities [Abstract]    
Available-for-sale securities, debt maturities, within 1 year, fair value [2] 5,482  
Available-for-sale securities, debt maturities, over 1 to 5 years, fair value [2] 394  
Available-for-sale securities, debt maturities, over 5 years, fair value [2] 3  
Available-for-sale securities, debt maturities [2] 5,878 7,823
Time deposits and other [Member]    
Debt Securities, Held-to-maturity, Maturity [Abstract]    
Held-to-maturity securities, debt maturities, total 668 1,091
Held-to-maturity securities, gross unrealized gains 0 0
Held-to-maturity securities, gross unrealized losses 0 0
Held-to-maturity securities, fair value 668 1,091
Debt Securities, Held-to-maturity, Maturity, Fair Value [Abstract]    
Held-to-maturity securities, debt maturities, within 1 year, fair value 610  
Held-to-maturity securities, debt maturities, over 1 to 5 years, fair value 24  
Held-to-maturity securities, debt maturities, over 5 years, fair value $ 35  
Money market funds [Member]    
Available-for-sale Equity Securities [Abstract]    
Available-for-sale equity securities, amortized cost [1]   2,115
Available-for-sale equity securities, gross unrealized gain [1]   0
Available-for-sale equity securities, gross unrealized losses [1]   0
Available-for-sale securities, equity securities [1]   2,115
Equity [Member]    
Available-for-sale Equity Securities [Abstract]    
Available-for-sale equity securities, amortized cost [1]   728
Available-for-sale equity securities, gross unrealized gain [1]   586
Available-for-sale equity securities, gross unrealized losses [1]   (124)
Available-for-sale securities, equity securities [1]   $ 1,190
[1] Upon the 2018 adoption of a new accounting standard related to financial assets and liabilities, available-for-sale equity securities were classified as equity securities. For additional information see Note 1B.
[2] Primarily issued by a diverse group of corporations.