Investment Securities (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares	Jun. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) Rate	May 03, 2024 USD ($) shares	Mar. 31, 2024 USD ($) shares	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items]
Equity Securities without Readily Determinable Fair Value, Amount	$ 8,853,000	$ 65,780,000	$ 9,828,000	$ 8,853,000	$ 9,083,000			$ 6,978,000
Percentage decrease requiring a review for impairment			20.00%
Fair value of securities on impairment watch list			$ 969,400,000		1,600,000,000
Debt Securities, Available-for-sale, Unrealized Loss Position			6,063,031,000		8,134,911,000
Unrealized Loss on AFS Debt Securities			731,380,000		994,534,000
AFS securities in loss position at period-end, change in unrealized loss			(263,200,000)
Debt Securities, Available-for-Sale, Planned Sale, Amortized Cost					$ 1,200,000,000
Debt Securities, Available-for-Sale, Planned Sale, Yield | Rate					2.10%
Loss on Available for Sale debt securities portfolio repositioning					$ 179,100,000
Debt Securities, Available-for-Sale, Planned Sale, Reinvestment					$ 928,800,000
Debt Securities, Available-for-Sale, Planned Sale, Yield of Reinvestment | Rate					4.60%
Securities pledged as collateral			$ 6,700,000,000		$ 6,900,000,000
Number of investments in a single issuer that exceed 10% of stockholder's equity			0
No investment in a single issuer exceeds this percentage of stockholder's equity			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			$ 419,300,000
Debt Securities, Available-for-sale, Unrealized Loss Position			880,828,000		1,846,004,000
Unrealized Loss on AFS Debt Securities			9,630,000		$ 41,859,000
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Losses realized on sales			(4,218,000)	192,938,000
Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Equity Securities, FV-NI, Gain (Loss)			1,666,000	$ 178,098,000
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
Proceeds from Sale of Equity Securities	$ 56,800,000	$ 119,800,000
Visa Class C Shares
Debt Securities, Available-for-sale [Line Items]
Exchange Offer, Common Shares Received | shares						163,404
Private Equity Securities
Debt Securities, Available-for-sale [Line Items]
Fair value other securities adjustments, net			$ 3,800,000