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Debt Securities (Schedule Of Amortized Cost, Gross Unrealized Gains And Losses, And Estimated Fair Value Of Securities Available For Sale And Securities Held To Maturity) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 27,265	$ 28,183
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	79	26
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(1,402)	(1,985)
Available-for-sale debt securities, net carrying value	25,942	26,224
Debt securities available for sale	25,942	26,224
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities held to maturity, amortized cost	6,070	5,170
Held To Maturity Debt Securities Gross Unrealized Gains	0	0
Held To Maturity Debt Securities Gross Unrealized Losses	(875)	(743)
Debt Securities held to maturity	5,195	4,427
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain	0	0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss	(132)	(201)
Debt Securities held to maturity, estimated fair value	5,063	4,226
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,129	2,088
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	6	2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(74)	(87)
Available-for-sale debt securities, net carrying value	2,061	2,003
Debt securities available for sale	2,061	2,003
Federal agency securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	493	460
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(12)	(17)
Available-for-sale debt securities, net carrying value	485	444
Debt securities available for sale	485	444
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2	2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Available-for-sale debt securities, net carrying value	2	2
Debt securities available for sale	2	2
Residential agency
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	19,600	20,482
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	59	20
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(1,076)	(1,557)
Available-for-sale debt securities, net carrying value	18,583	18,945
Debt securities available for sale	18,583	18,945
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities held to maturity, amortized cost	5,565	4,663
Held To Maturity Debt Securities Gross Unrealized Gains	0	0
Held To Maturity Debt Securities Gross Unrealized Losses	(875)	(743)
Debt Securities held to maturity	4,690	3,920
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain	0	0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss	(119)	(186)
Debt Securities held to maturity, estimated fair value	4,571	3,734
Commercial agency
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	4,309	4,389
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	7	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(221)	(300)
Available-for-sale debt securities, net carrying value	4,095	4,090
Debt securities available for sale	4,095	4,090
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities held to maturity, amortized cost	505	507
Held To Maturity Debt Securities Gross Unrealized Gains	0	0
Held To Maturity Debt Securities Gross Unrealized Losses	0	0
Debt Securities held to maturity	505	507
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Gain	0	0
Held-to-maturity Debt Securities, Accumulated Unrecognized Holding Loss	(13)	(15)
Debt Securities held to maturity, estimated fair value	492	492
Commercial non-agency
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	92	92
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(9)	(10)
Available-for-sale debt securities, net carrying value	83	82
Debt securities available for sale	83	82
Corporate and other debt securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	640	670
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3	2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(10)	(14)
Available-for-sale debt securities, net carrying value	633	658
Debt securities available for sale	$ 633	$ 658

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