Shareholders' Equity and Other Comprehensive Income (Loss) - Schedule of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Net of Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Beginning balance	$ 7,044	$ 6,432
Other comprehensive income (loss) before reclassifications	(98)	(6)
Amounts reclassified from AOCI	(4)	8
Total other comprehensive income	(102)	2
Ending balance	14,594	6,543
Unrealized losses on investment securities available for sale related to residual tax effects remaining in OCI	5	5
Total
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Beginning balance	(123)	(168)
Total other comprehensive income	(102)	2
Ending balance	(225)	(166)
Net unamortized holding (losses) gains on AFS securities transferred to HTM
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Beginning balance	12	18
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from AOCI	(1)	(2)
Total other comprehensive income	(1)	(2)
Ending balance	11	16
Net unrealized gains (losses) on investment securities AFS
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Beginning balance	(105)	(160)
Other comprehensive income (loss) before reclassifications	(97)	(14)
Amounts reclassified from AOCI	(3)	10
Total other comprehensive income	(100)	(4)
Ending balance	(205)	(164)
Net unrealized gains (losses) on cash flow hedges
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Beginning balance	(30)	(26)
Other comprehensive income (loss) before reclassifications	(1)	8
Amounts reclassified from AOCI	0	0
Total other comprehensive income	(1)	8
Ending balance	$ (31)	$ (18)

Debt Securities, Available For Sale, Unrealized Gain (Loss), Related To Residual Tax Effects Remaining In OCI

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