Consolidated Statements of (Loss) Income and Comprehensive (Loss) Income (Parenthetical) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Income Statement [Abstract]
Change in net unrealized loss on securities available for sale, tax	$ (71)	$ 69	$ (40)	$ 84
Change in pension and post-retirement obligations, tax	1	0	0	(1)
Change in net unrealized gain on cash flow hedges, tax	0	(17)	(36)	(26)
Reclassification adjustment for defined benefit plans, tax	(1)	0	(1)	0
Reclassification adjustment for net gain on cash flow hedges included in net income, tax	$ 5	$ 2	$ 15	$ 5

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Amount, after adjustment, of tax expense (benefit) for unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and tax expense (benefit) for unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.

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Amount, before reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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