v3.4.0.3
Debt (Debt) (Details) - USD ($)
$ in Millions
Mar. 31, 2016
Dec. 31, 2015
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations $ 11,877 $ 11,937
Debt, Current 205 221
Long-term Debt, Excluding Current Maturities 11,672 11,716
Unsecured Debt [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 3,408 3,406
Loans Payable [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 3,271 3,277
Corporate Debt Securities [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 1,790 1,789
Notes Payable, Other Payables [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 1,665 1,715
Secured Debt [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations 1,562 1,565
Capital Lease Obligations [Member]    
Debt Instrument [Line Items]    
Debt and Capital Lease Obligations $ 181 $ 185