Financial Derivatives - Schedule of Derivative Instruments in Statement of Financial Position (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Notional Disclosures [Abstract]
Notional Amount	$ 19,009,603	$ 17,547,367
Asset
Asset	26,329	19,139
Collateral (held)/pledged	0	0
Net amount	26,329	19,139
(Liability)
(Liability)	(105,574)	(34,248)
Collateral (held)/pledged	262,394	194,519
Net amount	156,820	160,271
Designated as hedge | Fair value hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	7,209,418	6,238,438
Asset
Asset	8,657	11,554
(Liability)
(Liability)	$ (1,589)	$ (583)
Weighted- Average Pay Rate	1.92%	2.06%
Weighted- Average Receive Rate	0.37%	0.13%
Weighted- Average Remaining Term (in years)	11 years	11 years 7 months 20 days
Designated as hedge | Fair value hedges: | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 6,565,729	$ 5,884,529
Asset
Asset	279	15
(Liability)
(Liability)	$ (11,149)	$ (8,383)
Weighted- Average Pay Rate	0.42%	0.17%
Weighted- Average Receive Rate	0.91%	0.88%
Weighted- Average Remaining Term (in years)	2 years 1 month 28 days	2 years 3 months 7 days
Designated as hedge | Fair value hedges: | Receive fixed callable
Notional Disclosures [Abstract]
Notional Amount	$ 1,883,577	$ 1,571,577
Asset
Asset	0	103
(Liability)
(Liability)	$ (90,594)	$ (17,612)
Weighted- Average Pay Rate	0.25%	0.01%
Weighted- Average Receive Rate	1.04%	0.80%
Weighted- Average Remaining Term (in years)	3 years 10 months 24 days	4 years 2 months 1 day
Designated as hedge | Cash flow hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 617,000	$ 570,000
Asset
Asset	15,900	6,905
(Liability)
(Liability)	$ (70)	$ (2,763)
Weighted- Average Pay Rate	1.92%	1.93%
Weighted- Average Receive Rate	0.74%	0.49%
Weighted- Average Remaining Term (in years)	5 years 7 months 20 days	5 years 8 months 19 days
No hedge designation
Asset
Credit valuation adjustment	$ (2)	$ 0
(Liability)
Credit valuation adjustment	29	14
No hedge designation | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	227,918	229,062
Asset
Asset	265	0
(Liability)
(Liability)	$ (1,638)	$ (4,641)
Weighted- Average Pay Rate	3.24%	3.22%
Weighted- Average Receive Rate	0.37%	0.16%
Weighted- Average Remaining Term (in years)	4 years 8 months 19 days	4 years 11 months 12 days
No hedge designation | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 1,038,750	$ 1,377,250
Asset
Asset	0	0
(Liability)
(Liability)	$ 0	$ 0
Weighted- Average Pay Rate	0.35%	0.13%
Weighted- Average Receive Rate	0.40%	0.43%
Weighted- Average Remaining Term (in years)	10 months 13 days	11 months 19 days
No hedge designation | Basis swaps
Notional Disclosures [Abstract]
Notional Amount	$ 1,393,911	$ 1,608,911
Asset
Asset	191	489
(Liability)
(Liability)	$ (435)	$ (280)
Weighted- Average Pay Rate	0.45%	0.17%
Weighted- Average Receive Rate	0.48%	0.20%
Weighted- Average Remaining Term (in years)	3 years 6 months 21 days	3 years 3 months 21 days
No hedge designation | Treasury futures
Notional Disclosures [Abstract]
Notional Amount	$ 73,300	$ 67,600
Asset
Asset	1,039	73
(Liability)
(Liability)	$ (128)	$ 0
Weighted- Average Forward Price (in dollars per share)	$ 124.12	$ 130.58