Derivative Financial Instruments - Dealer Counterparties and Central Clearing Parties (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Credit Derivatives [Line Items]
Unsecured positions in a net gain with counterparties after collateral postings	$ 749	$ 684
Asset Pledged as Collateral
Credit Derivatives [Line Items]
Securities, fair value	39,702	38,012
Dealer and other counterparties:
Credit Derivatives [Line Items]
Cash and other collateral received from counterparties	702	542
Derivatives in a net gain position	787	618
Unsecured positions in a net gain with counterparties after collateral postings	83	76
Cash collateral posted	789	590
Derivatives in a net loss position	855	692
Central counterparties clearing:
Credit Derivatives [Line Items]
Cash and other collateral received from counterparties	0	4
Derivatives in a net gain position	16	12
Cash collateral posted	12	45
Derivatives in a net loss position	0	13
Central counterparties clearing: | Asset Pledged as Collateral
Credit Derivatives [Line Items]
Securities, fair value	$ 1,112	$ 639