v3.5.0.2
Debt (Debt) (Details) - USD ($)
$ in Millions
Sep. 30, 2016
Dec. 31, 2015
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations $ 11,820 $ 11,937
Debt, Current 197 221
Long-term Debt, Excluding Current Maturities 11,623 11,716
Unsecured Debt [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 3,410 3,406
Loans Payable [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 2,637 3,277
Corporate Debt Securities [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 2,408 1,789
Notes Payable, Other Payables [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 1,628 1,715
Secured Debt [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 1,556 1,565
Capital Lease Obligations [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations $ 181 $ 185