Collateral and Offsetting of Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Offsetting Assets [Line Items]
Maximum loss after applying netting agreements and collateral	$ 1,942	$ 359
Securities Purchased Under Agreements To Resell Accrued Interest Receivable	12	18
Reduction In Debt		9,800
Secured lending but not yet paid	100
Commitments
Offsetting Assets [Line Items]
Total exposure on our commitments	1,142	61
OTC derivatives
Offsetting Assets [Line Items]
Maximum loss after applying netting agreements and collateral	80	20
Cash pledged to us as collateral that was invested as part of our liquidity and contingency operating portfolio	6,400	2,600
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell
Offsetting Assets [Line Items]
Securities Held as Collateral, at Fair Value	53,300	52,400
Securities purchased under agreements to resell not executed with clearinghouse
Offsetting Assets [Line Items]
Securities Held as Collateral, at Fair Value	$ 1,000	$ 2,400