Derivative and Hedging Activities - Company's Carrying Amounts on our Hedged Loans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loans and leases	$ 840	$ 1,167	$ 1,700	$ 2,360
U. S. Treasury obligations
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Items	1,013		1,013		$ 0
Cumulative Amount of Fair Value Hedging Adjustments	14		14		0
GSE CMOs
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Items	1,999		1,999		0
Cumulative Amount of Fair Value Hedging Adjustments	10		10		0
GSE debentures
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Items	1,262		1,262		0
Cumulative Amount of Fair Value Hedging Adjustments	7		7		0
Debt securities available-for-sale
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Items	4,274		4,274		0
Cumulative Amount of Fair Value Hedging Adjustments	31		31		0
Loans and leases held-for-investment
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Items	3,401		3,401		5,861
Cumulative Amount of Fair Value Hedging Adjustments	(9)		(9)		$ (18)
Loans and leases	$ 0	$ 0	$ 7	$ 17