Derivatives - Interest Rate Swap Contracts, Swaptions and Futures Contracts (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Derivative [Line Items]
Notional Amount	$ 6,910,000,000	$ 7,210,000,000
Weighted Average Remaining Term (Months)	79 months	77 months
Weighted Average Rate	0.75%	0.63%
Notional amount, forward settling	$ 550,000,000
Fed Funds Effective Rate Overnight Index Swap Rate
Derivative [Line Items]
Notional Amount	6,007,000,000	$ 6,007,000,000
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Derivative [Line Items]
Notional Amount	$ 903,000,000	$ 1,203,000,000
Less than 3 years
Derivative [Line Items]
Derivative, remaining maturity	3 years	3 years
Notional Amount	$ 1,066,000,000	$ 1,593,000,000
Weighted Average Remaining Term (Months)	16 months	15 months
Weighted Average Rate	0.10%	0.08%
Greater than or equal to 3 years and less than 5 years
Derivative [Line Items]
Notional Amount	$ 1,342,000,000	$ 708,000,000
Weighted Average Remaining Term (Months)	55 months	57 months
Weighted Average Rate	0.59%	0.24%
Greater than or equal to 5 years and less than 7 years
Derivative [Line Items]
Notional Amount	$ 100,000,000	$ 707,000,000
Weighted Average Remaining Term (Months)	81 months	64 months
Weighted Average Rate	1.04%	0.88%
Greater than or equal to 7 years
Derivative [Line Items]
Notional Amount	$ 4,402,000,000	$ 4,202,000,000
Weighted Average Remaining Term (Months)	102 months	107 months
Weighted Average Rate	0.95%	0.87%
Minimum | Greater than or equal to 3 years and less than 5 years
Derivative [Line Items]
Derivative, remaining maturity	3 years	3 years
Minimum | Greater than or equal to 5 years and less than 7 years
Derivative [Line Items]
Derivative, remaining maturity	5 years	5 years
Maximum | Greater than or equal to 3 years and less than 5 years
Derivative [Line Items]
Derivative, remaining maturity	5 years	5 years
Maximum | Greater than or equal to 5 years and less than 7 years
Derivative [Line Items]
Derivative, remaining maturity	7 years	7 years
Maximum | Greater than or equal to 7 years
Derivative [Line Items]
Derivative, remaining maturity	7 years	7 years