Offsetting Assets and Liabilities - Assets (Details) - USD ($) $ in Millions		Sep. 30, 2021	Dec. 31, 2020
Derivatives:
Gross Amounts of Recognized Assets		$ 5,687	$ 5,870
Amounts of Assets Presented in the Consolidated Balance Sheets		5,687	5,870
Gross Amounts Not Offset in the Consolidated Balance Sheets
Financial Instruments	[1]	(3,604)	(3,978)
Cash Collateral		(1,582)	(1,452)
Securities Collateral		(404)	(315)
Net Amount		97	125
Securities borrowed
Gross Amounts of Recognized Assets		63	147
Amounts of Assets Presented in the Consolidated Balance Sheets		63	147
Gross Amounts Not Offset in the Consolidated Balance Sheets
Financial Instruments	[1]	(16)	(43)
Securities Collateral		(45)	(103)
Net Amount		2	1
Total
Gross Amounts of Recognized Assets		5,750	6,017
Amounts of Assets Presented in the Consolidated Balance Sheets		5,750	6,017
Gross Amounts Not Offset in the Consolidated Balance Sheets
Financial Instruments	[1]	(3,620)	(4,021)
Cash Collateral		(1,582)	(1,452)
Securities Collateral		(449)	(418)
Net Amount		99	126
OTC
Derivatives:
Gross Amounts of Recognized Assets		5,310	5,501
Amounts of Assets Presented in the Consolidated Balance Sheets		5,310	5,501
Gross Amounts Not Offset in the Consolidated Balance Sheets
Financial Instruments	[1]	(3,479)	(3,862)
Cash Collateral		(1,369)	(1,287)
Securities Collateral		(404)	(315)
Net Amount		58	37
OTC cleared
Derivatives:
Gross Amounts of Recognized Assets		25	58
Amounts of Assets Presented in the Consolidated Balance Sheets		25	58
Gross Amounts Not Offset in the Consolidated Balance Sheets
Financial Instruments	[1]	(15)	(25)
Net Amount		10	33
Exchange-traded
Derivatives:
Gross Amounts of Recognized Assets		352	311
Amounts of Assets Presented in the Consolidated Balance Sheets		352	311
Gross Amounts Not Offset in the Consolidated Balance Sheets
Financial Instruments	[1]	(110)	(91)
Cash Collateral		(213)	(165)
Net Amount		$ 29	$ 55

[1] Represents the amount of assets that could be offset by liabilities with the same counterparty under master netting or similar arrangements that management elects not to offset on the Consolidated Balance Sheets.