Quarterly report pursuant to Section 13 or 15(d)

Investments (Details 5)

v3.7.0.1
Investments (Details 5) - USD ($)
$ in Millions
Jun. 30, 2017
Dec. 31, 2016
Investments [Abstracts]    
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis $ 2,261  
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value 2,305  
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Amortized Cost Basis 3,358  
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Fair Value 3,385  
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Amortized Cost Basis 142  
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Fair Value 158  
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis 315  
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value 323  
Available-for-sale Securities, Amortized Cost Basis 7,344 $ 5,952
Available-for-sale Securities Fair Value 8,042 6,413
Cost Method Investments [Abstract]    
Cost-method Investments, Aggregate Carrying Amount 144 140
Equity Securities [Member]    
Investments [Abstracts]    
Available-for-sale Securities, Amortized Cost Basis 1,268 1,252
Available-for-sale Securities Fair Value $ 1,871 $ 1,655