v3.6.0.2
Debt (Debt) (Details) - USD ($)
$ in Millions
Dec. 31, 2016
Dec. 31, 2015
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations $ 12,179 $ 11,937
Debt, current portion 748 221
Debt, net of current portion 11,431 11,716
Unsecured Debt [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 3,412 3,406
Loans Payable [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 3,165 3,277
Corporate Debt Securities [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 2,290 1,789
Notes Payable, Other Payables [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 1,597 1,715
Secured Debt [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 1,553 1,565
Capital Lease Obligations [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations $ 162 $ 185