v3.4.0.3
Debt Senior Unsecured Notes (Details) - USD ($)
$ in Millions
Mar. 31, 2016
Dec. 31, 2015
Debt Instrument [Line Items]    
Long-term Debt $ 11,674 $ 11,292
Senior Unsecured Notes 2023 [Member]    
Debt Instrument [Line Items]    
Long-term Debt 1,235 1,235
Senior Unsecured Notes 2024 [Member]    
Debt Instrument [Line Items]    
Long-term Debt 642 641
Senior Unsecured Notes 2025 [Member]    
Debt Instrument [Line Items]    
Long-term Debt 1,531 1,530
Unsecured Debt [Member]    
Debt Instrument [Line Items]    
Long-term Debt $ 3,408 $ 3,406