Derivative Instruments and Hedging Activities - Offsetting Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Derivatives liabilities(1)
Derivative Liabilities, Gross Amount	$ 795	$ 520
Derivative Liability, Offsetting Financial Instruments	(200)	(86)
Derivative Liability, Offsetting Cash Collateral	(150)	(57)
Derivative Liability	445	377
Derivative Liability, Securities Collateral Not Netted	0	0
Net Exposure	445	377
Derivative Liability, Not Subject to Master Netting Arrangement	364	314
Repurchase agreements(2)(3)
Gross Amounts	917	969
Securities Sold under Agreements to Repurchase, Asset	0	0
Repurchase Agreement, Collateral, Right To Reclaim Cash, Offset	0	0
Net Amounts as Recognized	917	969
Offsetting Amounts Not Netted, Collateral Pledged	(917)	(969)
Net Exposure	0	$ 0
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	$ 936