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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

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Derivative Instruments and Hedging Activities - Gains (Losses) on Accounting Hedges and Fair Value Hedges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Cash flow hedges - Interest rate contracts
Recognized in OCI	$ 15.0	$ 34.0	$ 28.0	$ (26.0)
Less: Realized gains (losses) (pre-tax) reclassified from AOCI to interest income	(40.0)	(11.0)	(70.0)	(34.0)
Net change in cash flow hedges included within AOCI	55.0	45.0	98.0	8.0
Cash flow hedges expected to be reclassified from AOCI			$ (60.0)
Maximum length of time over which forecasted cash flows are hedged			40 months
Borrowings
Amortized cost	600.0		$ 600.0		$ 325.0
Hedged asset, unallocated basis adjustment	703.0		703.0		178.0
Amortized cost, unalloccated basis adjustment	2.2		2.2		(2.0)
Investment securities—AFS
Fair Value Hedges - Hedged Items
Amortized cost basis/ carrying amount currently or previously hedged	57,275.0		57,275.0		54,809.0
Basis adjustments included in amortized cost/ carrying amount	218.0		218.0		(741.0)
Deposits
Fair Value Hedges - Hedged Items
Amortized cost basis/ carrying amount currently or previously hedged	48,904.0		48,904.0		21,524.0
Basis adjustments included in amortized cost/ carrying amount	156.0		156.0		44.0
Borrowings
Borrowings
Carrying amount currently or previously hedged	189,937.0		189,937.0		171,834.0
Basis adjustments included in carrying amount—Outstanding hedges	(5,769.0)		(5,769.0)		(10,072.0)
Basis adjustments included in carrying amount—Terminated hedges	(631.0)		(631.0)		$ (648.0)
Fair Value Hedges \| Interest Income \| Interest rate
Gain (Loss) on Fair Value Hedges Recognized in Interest Expense
Gains (losses) recognized in interest expense	(100.0)	(1,277.0)	(903.0)	(686.0)
Fair Value Hedges \| Interest Income \| Investment securities—AFS
Gain (Loss) on Fair Value Hedges Recognized in Interest Expense
Gains (losses) recognized in interest expense	115.0	1,302.0	938.0	755.0
Fair Value Hedges \| Interest Expense \| Interest rate
Gain (Loss) on Fair Value Hedges Recognized in Interest Expense
Gains (losses) recognized in interest expense	609.0	5,777.0	4,471.0	3,627.0
Fair Value Hedges \| Interest Expense \| Deposits
Gain (Loss) on Fair Value Hedges Recognized in Interest Expense
Gains (losses) recognized in interest expense	(34.0)	(227.0)	(112.0)	(235.0)
Fair Value Hedges \| Interest Expense \| Borrowings
Gain (Loss) on Fair Value Hedges Recognized in Interest Expense
Gains (losses) recognized in interest expense	(574.0)	(5,561.0)	(4,364.0)	(3,403.0)
Net Investment Hedges \| Foreign exchange
Net investment hedges—Foreign exchange contracts
Recognized in OCI	175.0	(533.0)	(1,229.0)	122.0
Forward points excluded from hedge effectiveness testing—Recognized in Interest income	$ 96.0	$ 50.0	$ 143.0	$ 140.0