Accumulated Other Comprehensive (Loss) Income - Schedule of Changes in Components of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity	$ 19,771	$ 10,642	$ 9,662	$ 4,738
AOCI activity before reclassifications			(165)	(747)
Amounts reclassified from AOCI to earnings			20	8
Other comprehensive loss, net of tax	(108)	(264)	(145)	(739)
Ending balance, shareholders' equity	20,389	9,833	20,389	9,833
Total accumulated other comprehensive (loss) income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity	(772)	(465)	(735)	10
Other comprehensive loss, net of tax	(108)	(264)	(145)	(739)
Ending balance, shareholders' equity	(880)	(729)	(880)	(729)
Unrealized loss on securities available for sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity			(739)	(9)
AOCI activity before reclassifications			(169)	(747)
Amounts reclassified from AOCI to earnings			19	0
Other comprehensive loss, net of tax			(150)	(747)
Ending balance, shareholders' equity	(889)	(756)	(889)	(756)
Unrealized loss on securities available for sale transferred to held to maturity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity			(6)	(7)
AOCI activity before reclassifications	0	0	0	0
Amounts reclassified from AOCI to earnings			1	1
Other comprehensive loss, net of tax	0	0	1	1
Ending balance, shareholders' equity	(5)	(6)	(5)	(6)
Defined benefit pension items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity			10	26
AOCI activity before reclassifications	0	0	4	0
Amounts reclassified from AOCI to earnings			0	7
Other comprehensive loss, net of tax	0	2	4	7
Ending balance, shareholders' equity	$ 14	$ 33	$ 14	$ 33