Investments (Narrative) (Details)			12 Months Ended
	Oct. 01, 2021 USD ($)	Nov. 01, 2020 USD ($)	Dec. 31, 2021 USD ($) investment shares	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Schedule of Investments [Line Items]
Investment securities available for sale transferred to held to maturity fair value, net of tax	$ (12,700,000)	$ 5,900,000	$ (12,659,000)	$ 5,894,000	$ 72,512,000
Reclassification of unrealized losses, net of tax	9,700,000	4,500,000	(10,883,000)	4,157,000	$ 71,149,000
Interest receivable, available-for-sale debt securities			22,300,000	17,600,000
Interest receivable, held-to-maturity debt securities			6,600,000	5,400,000
Debt securities, accrued interest, writeOff			$ 0	0
Number of investments in continuous unrealized loss position for more than twelve months | investment			37
Unrealized losses related to marketability of securities or issuers ability to honor redemption obligations			$ 0
Investment value deemed to be OTTI			0
Investment securities, aggregate carrying value, pledged as collateral			5,740,000,000	$ 4,640,000,000
Debt securities, held-to-maturity, nonaccrual			$ 0
Visa Class B Common Stock
Schedule of Investments [Line Items]
Investment owned (in shares) | shares			353,577
Total past due
Schedule of Investments [Line Items]
Debt securities			$ 0
Mortgage Backed Securities
Schedule of Investments [Line Items]
Investment securities available for sale transferred to held to maturity amortized cost	451,700,000	1,460,000,000
Investment securities available for sale transferred to held to maturity fair value	$ 439,000,000	$ 1,470,000,000
Weighted average contractual maturity (years)		18 years