Investment Securities - Investment Available for Sale (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 87,047	$ 94,871
Allowance for Credit Losses	(3)	(1)
Gross Unrealized Gains	154	1,387
Gross Unrealized Losses	(10,279)	(996)
Securities available for sale (amortized cost of $87.0 billion and $94.9 billion and allowance for credit losses of $3 million and $1 million as of December 31, 2022 and 2021, respectively)	76,919	95,261
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	5,129	9,419
Allowance for Credit Losses	0	0
Gross Unrealized Gains	2	23
Gross Unrealized Losses	(90)	0
Securities available for sale (amortized cost of $87.0 billion and $94.9 billion and allowance for credit losses of $3 million and $1 million as of December 31, 2022 and 2021, respectively)	5,041	9,442
RMBS, Agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	71,212	72,593
Allowance for Credit Losses	0	0
Gross Unrealized Gains	53	958
Gross Unrealized Losses	(9,413)	(931)
Securities available for sale (amortized cost of $87.0 billion and $94.9 billion and allowance for credit losses of $3 million and $1 million as of December 31, 2022 and 2021, respectively)	61,852	72,620
RMBS, Non-agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	653	792
Allowance for Credit Losses	(3)	(1)
Gross Unrealized Gains	93	205
Gross Unrealized Losses	(6)	0
Securities available for sale (amortized cost of $87.0 billion and $94.9 billion and allowance for credit losses of $3 million and $1 million as of December 31, 2022 and 2021, respectively)	737	996
RMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	71,865	73,385
Allowance for Credit Losses	(3)	(1)
Gross Unrealized Gains	146	1,163
Gross Unrealized Losses	(9,419)	(931)
Securities available for sale (amortized cost of $87.0 billion and $94.9 billion and allowance for credit losses of $3 million and $1 million as of December 31, 2022 and 2021, respectively)	62,589	73,616
CMBS, Agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,626	9,237
Allowance for Credit Losses	0	0
Gross Unrealized Gains	4	195
Gross Unrealized Losses	(760)	(63)
Securities available for sale (amortized cost of $87.0 billion and $94.9 billion and allowance for credit losses of $3 million and $1 million as of December 31, 2022 and 2021, respectively)	7,870	9,369
Other securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,427	2,830
Allowance for Credit Losses	0	0
Gross Unrealized Gains	2	6
Gross Unrealized Losses	(10)	(2)
Securities available for sale (amortized cost of $87.0 billion and $94.9 billion and allowance for credit losses of $3 million and $1 million as of December 31, 2022 and 2021, respectively)	1,419	2,834
Asset-backed Securities
Debt Securities, Available-for-sale [Line Items]
Securities available for sale (amortized cost of $87.0 billion and $94.9 billion and allowance for credit losses of $3 million and $1 million as of December 31, 2022 and 2021, respectively)	$ 707	$ 2,000
US Treasury and Agency securities \| Available-for-sale securities \| Government Contracts Concentration Risk
Debt Securities, Available-for-sale [Line Items]
Percentage of portfolio	97.00%	96.00%

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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