Derivative Instruments (Offsetting Assets and Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Derivatives Assets
Gross Amounts of Recognized Financial Instruments	$ 1,470,068	$ 1,477,909
Gross Amounts Offset in the Statements of Financial Position	(1,098,964)	(1,474,780)
Net Amounts Presented in the Statements of Financial Position	371,104	3,129
Financial Instruments/Collateral	(80,145)	0
Net Amount	290,959	3,129
Securities Purchased under Agreements to Resell
Gross Amounts of Recognized Financial Instruments	0	0
Gross Amounts Offset in the Statements of Financial Position	0	0
Net Amounts Presented in the Statements of Financial Position	0	0
Financial Instruments/Collateral	0	0
Net Amount	0	0
Total Assets
Gross Amounts of Recognized Financial Instruments	1,470,068	1,477,909
Gross Amounts Offset in the Statements of Financial Position	(1,098,964)	(1,474,780)
Net Amounts Presented in the Statements of Financial Position	371,104	3,129
Financial Instruments/Collateral	(80,145)	0
Net Amount	290,959	3,129
Derivatives Liabilities
Gross Amounts of Recognized Financial Instruments	1,809,791	1,368,213
Gross Amounts Offset in the Statements of Financial Position	(1,809,791)	(1,153,610)
Net Amounts Presented in the Statements of Financial Position	0	214,603
Financial Instruments/Collateral	0	(214,603)
Net Amount	0	0
Securities sold under agreement to repurchase
Gross Amounts of Recognized Financial Instruments	0	0
Gross amounts Offset in the Statements of Financial Position	0	0
Net Amounts Presented in the Statements of Financial Position	0	0
Financial Instruments/Collateral	0	0
Net Amount	0	0
Total Liabilities
Gross Amounts of Recognized Financial Instruments	1,809,791	1,368,213
Gross amounts Offset in the Statements of Financial Position Agreements to Repurchase, Securities Loaned, Asset	(1,809,791)	(1,153,610)
Net Amounts Presented in the Statements of Financial Position	0	214,603
Financial Instruments/Collateral	0	(214,603)
Net Amount	$ 0	$ 0