Derivatives and Hedging Activities - Outstanding Interest Rate Swaptions and Derivative Instrument Information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($)
Derivative Interest Rate Swaptions
Notional amount, beginning balance	$ 8,150,000
Additions	500,000
Settlement, Termination, Expiration or Exercise	(775,000)
Notional amount, ending balance	7,875,000
Interest Rate Swaps
Derivative Interest Rate Swaptions
Notional amount, beginning balance	8,150,000
Additions	500,000
Settlement, Termination, Expiration or Exercise	(775,000)
Notional amount, ending balance	7,875,000
TBA Purchase Contracts
Derivative Interest Rate Swaptions
Notional amount, beginning balance	400,000
Additions	1,150,000
Settlement, Termination, Expiration or Exercise	(1,550,000)
Notional amount, ending balance	0
TBA Sale Contracts
Derivative Interest Rate Swaptions
Notional amount, beginning balance	(400,000)
Additions	(1,150,000)
Settlement, Termination, Expiration or Exercise	1,550,000
Notional amount, ending balance	0
Interest Rate Swap, Fixed Rate
Derivative Interest Rate Swaptions
Notional amount, beginning balance	5,800,000
Notional amount, ending balance	6,300,000
Interest Rate Swap, Variable Rate | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Derivative Interest Rate Swaptions
Notional amount, beginning balance	2,350,000
Notional amount, ending balance	$ 1,575,000