Financial Derivatives - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Derivative [Line Items]
Gain expected to be reclassified from AOCI to earnings over next 12 months	$ 1,200,000
Gain (loss) from interest rate swaps designated as cash flow hedges reclassified to earnings	0	$ 0
Investments held as collateral	0		$ 0
Financial derivatives in net payable position	0		0
Notional amount	19,009,603,000		17,547,367,000
Exchange Cleared
Derivative [Line Items]
Notional amount	16,000,000,000		14,900,000,000
Interest Rate Swap
Derivative [Line Items]
Notional amount	18,900,000,000		17,500,000,000
Cash
Derivative [Line Items]
Cash posted as collateral	78,500,000		16,600,000
Available-for-Sale Securities
Derivative [Line Items]
Cash posted as collateral	$ 183,900,000		$ 177,900,000