Derivative Financial Instruments - Dealer Counterparties and Central Clearing Parties (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Credit Derivatives [Line Items]
Unsecured positions in a net gain with counterparties after collateral postings	$ 2,369	$ 3,834
Dealer Counterparties
Credit Derivatives [Line Items]
Cash and other collateral received from counterparties	346	446
Derivatives in a net gain position secured by collateral received	506	585
Unsecured positions in a net gain with counterparties after collateral postings	143	49
Cash collateral posted	1,704	1,524
Derivatives in a net loss position	2,591	1,604
Additional collateral that would have been posted had the Company’s credit ratings dropped below investment grade	3	3
Central Clearing Parties
Credit Derivatives [Line Items]
Derivatives in a net gain position secured by collateral received	0	5
Cash collateral posted	31	172
Derivatives in a net loss position	18	90
Securities pledged to central counterparties clearing	$ 904	$ 1,281