Investment Securities (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) $ / shares Rate shares	Jun. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2024 USD ($) $ / shares Rate shares	Sep. 30, 2023 USD ($)	May 03, 2024 USD ($) shares	Mar. 31, 2024 USD ($) shares	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items]
Proceeds from Sale of Equity Securities	$ 56,800,000	$ 119,800,000
Equity Securities without Readily Determinable Fair Value, Amount	8,853,000	$ 65,780,000	$ 8,853,000				$ 6,978,000
Percentage decrease requiring a review for impairment			20.00%
Fair value of securities on impairment watch list	814,500,000		$ 814,500,000				1,200,000,000
Debt Securities, Available-for-sale, Unrealized Loss Position	7,274,332,000		7,274,332,000				9,593,950,000
Unrealized Loss on AFS Debt Securities	818,814,000		818,814,000				1,220,484,000
AFS securities in loss position at period-end, change in unrealized loss			(401,700,000)
Debt Securities, Available-for-Sale, Planned Sale, Amortized Cost	$ 1,200,000,000		$ 1,200,000,000
Debt Securities, Available-for-Sale, Planned Sale, Yield | Rate	2.10%		2.10%
Loss on Available for Sale debt securities portfolio repositioning	$ 179,100,000		$ 179,100,000
Debt Securities, Available-for-Sale, Planned Sale, Reinvestment	$ 928,800,000		$ 928,800,000
Debt Securities, Available-for-Sale, Planned Sale, Yield of Reinvestment | Rate	4.60%		4.60%
Securities pledged as collateral	$ 6,200,000,000		$ 6,200,000,000				7,500,000,000
Number of investments in a single issuer that exceed 10% of stockholder's equity	0		0
No investment in a single issuer exceeds this percentage of stockholder's equity	10.00%		10.00%
U.S. government and federal agency obligations
Debt Securities, Available-for-sale [Line Items]
U.S. Treasury inflation-protected securities held, at fair value	$ 411,000,000.0		$ 411,000,000.0
Debt Securities, Available-for-sale, Unrealized Loss Position	716,996,000		716,996,000				765,985,000
Unrealized Loss on AFS Debt Securities	$ 13,379,000		13,379,000				$ 24,834,000
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Losses realized on sales			192,938,000	$ 8,587,000
Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Equity Securities, FV-NI, Gain (Loss)			178,098,000	(757,000)
Other Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Fair value other securities adjustments, net			$ 20,205,000	$ 16,946,000
Visa Class B-1 Shares
Debt Securities, Available-for-sale [Line Items]
Equity Securities without Readily Determinable Fair Value, Shares | shares						823,447
Equity Securities without Readily Determinable Fair Value, Carrying Value						$ 0
Exchange Offer, Original Shares Held | shares						823,447
Visa Class B-2 Shares
Debt Securities, Available-for-sale [Line Items]
Exchange Offer, Common Shares Received | shares					411,723
Equity Securities without Readily Determinable Fair Value, Amount					$ 0
Visa Class A Shares
Debt Securities, Available-for-sale [Line Items]
Exchange Offer, Conversion Rate of Common Stock					1.5875
Equity Securities Sold, Shares | shares	218,000	436,000	218,000
Equity Securities Sold, Average Price | $ / shares	$ 260.56	$ 274.91	$ 260.56
Visa Class C Shares
Debt Securities, Available-for-sale [Line Items]
Exchange Offer, Common Shares Received | shares					163,404