Derivative Financial Instruments - Dealer Counterparties and Central Clearing Parties (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Credit Derivatives [Line Items]
Unsecured positions in a net gain with counterparties after collateral postings	$ 1,386	$ 2,369
Asset Pledged as Collateral
Credit Derivatives [Line Items]
Securities, fair value	28,837	29,678
Dealer and other counterparties:
Credit Derivatives [Line Items]
Cash and other collateral received from counterparties	362	346
Derivatives in a net gain position	467	506
Unsecured positions in a net gain with counterparties after collateral postings	110	143
Cash collateral posted	1,045	1,704
Derivatives in a net loss position	1,289	2,591
Additional collateral that would have been posted had the Company’s credit ratings dropped below investment grade	0	3
Central counterparties clearing:
Credit Derivatives [Line Items]
Derivatives in a net gain position	2	0
Cash collateral posted	45	31
Derivatives in a net loss position	36	18
Central counterparties clearing: | Asset Pledged as Collateral
Credit Derivatives [Line Items]
Securities, fair value	$ 808	$ 904