Derivative Instruments and Hedging Activities - Offsetting Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative liabilities
Derivative Liabilities, Gross Amount	$ 1,201	$ 1,268
Derivative Liability, Offsetting Financial Instruments	(205)	(202)
Derivative Liability, Offsetting Cash Collateral	(82)	(460)
Derivative Liability	914	606
Derivative Liability, Securities Collateral Not Netted	0	0
Net Exposure	914	606
Repurchase agreements
Gross Amounts	352	576
Securities Sold under Agreements to Repurchase, Asset	0	0
Repurchase Agreement, Collateral, Right To Reclaim Cash, Offset	0	0
Net Amounts as Recognized	352	576
Offsetting Amounts Not Netted, Collateral Pledged	(352)	(576)
Net Exposure	0	0
Derivative, Collateral, Obligation to Return Cash	925	91
Derivative, Collateral, Obligation to Return Securities	1	1
Derivative, Collateral, Right to Reclaim Cash	633	$ 966
Decrease/(Increase) In Derivative Assets Due To LCH Rulebook Change	431
Decrease In Derivative Liabilities Due To LCH Rulebook Change	397
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	$ 359

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