Investment Securities (Contractual Maturity of Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Total securities available-for-sale at amortized cost
1 Year or Less	$ 672
After 1 Year through 5 Years	15,217
After 5 Years through 10 Years	15,560
After 10 Years	34,575
Total	66,024	$ 65,498
Available-for-sale, fair value
1 Year or Less	670
After 1 Year through 5 Years	15,142
After 5 Years through 10 Years	15,374
After 10 Years	32,132
Total	$ 63,318	62,039
Weighted-average yield, GAAP basis, available for sale securities	3.86%
Total securities held-to-maturity at amortized cost
1 Year or Less	$ 9,479
After 1 Year through 5 Years	18,174
After 5 Years through 10 Years	3,657
After 10 Years	43,147
Total	74,457	77,693
Held-to-maturity, fair value
1 Year or Less	9,411
After 1 Year through 5 Years	17,811
After 5 Years through 10 Years	3,538
After 10 Years	40,166
Total	$ 70,926	73,058
Weighted-average yield, GAAP basis, held to maturity securities	2.43%
1 Year or Less
Available-for-sale, fair value
Weighted-average yield, GAAP basis, available for sale securities	3.18%
Held-to-maturity, fair value
Weighted-average yield, GAAP basis, held to maturity securities	1.31%
After 1 Year through 5 Years
Available-for-sale, fair value
Weighted-average yield, GAAP basis, available for sale securities	3.68%
Held-to-maturity, fair value
Weighted-average yield, GAAP basis, held to maturity securities	1.78%
After 5 Years through 10 Years
Available-for-sale, fair value
Weighted-average yield, GAAP basis, available for sale securities	4.17%
Held-to-maturity, fair value
Weighted-average yield, GAAP basis, held to maturity securities	2.74%
After 10 Years
Available-for-sale, fair value
Weighted-average yield, GAAP basis, available for sale securities	3.82%
Held-to-maturity, fair value
Weighted-average yield, GAAP basis, held to maturity securities	2.92%
U.S. Treasury and government agencies
Total securities available-for-sale at amortized cost
1 Year or Less	$ 376
After 1 Year through 5 Years	10,961
After 5 Years through 10 Years	11,246
After 10 Years	2,171
Total	24,754	23,962
Available-for-sale, fair value
Total	24,504	23,551
Total securities held-to-maturity at amortized cost
1 Year or Less	9,187
After 1 Year through 5 Years	16,300
After 5 Years through 10 Years	1,447
After 10 Years	855
Total	27,789	29,420
Held-to-maturity, fair value
Total	27,185	28,524
Residential mortgage-backed | Mortgage-backed Securities Agency
Total securities available-for-sale at amortized cost
1 Year or Less	3
After 1 Year through 5 Years	310
After 5 Years through 10 Years	3,502
After 10 Years	29,342
Total	33,157
Total securities held-to-maturity at amortized cost
1 Year or Less	0
After 1 Year through 5 Years	7
After 5 Years through 10 Years	335
After 10 Years	39,036
Total	39,378
Residential mortgage-backed | Mortgage-backed Securities Non-agency
Total securities available-for-sale at amortized cost
1 Year or Less	0
After 1 Year through 5 Years	0
After 5 Years through 10 Years	47
After 10 Years	442
Total	489
Total securities held-to-maturity at amortized cost
1 Year or Less	0
After 1 Year through 5 Years	0
After 5 Years through 10 Years	0
After 10 Years	236
Total	236
Commercial mortgage servicing rights | Mortgage-backed Securities Agency
Total securities available-for-sale at amortized cost
1 Year or Less	60
After 1 Year through 5 Years	1,422
After 5 Years through 10 Years	151
After 10 Years	915
Total	2,548
Total securities held-to-maturity at amortized cost
1 Year or Less	0
After 1 Year through 5 Years	277
After 5 Years through 10 Years	437
After 10 Years	208
Total	922
Commercial mortgage servicing rights | Mortgage-backed Securities Non-agency
Total securities available-for-sale at amortized cost
1 Year or Less	0
After 1 Year through 5 Years	100
After 5 Years through 10 Years	82
After 10 Years	431
Total	613
Total securities held-to-maturity at amortized cost
1 Year or Less	0
After 1 Year through 5 Years	36
After 5 Years through 10 Years	0
After 10 Years	608
Total	644
Asset-backed
Total securities available-for-sale at amortized cost
1 Year or Less	0
After 1 Year through 5 Years	834
After 5 Years through 10 Years	316
After 10 Years	1,139
Total	2,289
Total securities held-to-maturity at amortized cost
1 Year or Less	8
After 1 Year through 5 Years	776
After 5 Years through 10 Years	1,164
After 10 Years	978
Total	2,926
Other
Total securities available-for-sale at amortized cost
1 Year or Less	233
After 1 Year through 5 Years	1,590
After 5 Years through 10 Years	216
After 10 Years	135
Total	2,174	2,307
Available-for-sale, fair value
Total	2,118	2,231
Total securities held-to-maturity at amortized cost
1 Year or Less	284
After 1 Year through 5 Years	778
After 5 Years through 10 Years	274
After 10 Years	1,226
Total	2,562	2,691
Held-to-maturity, fair value
Total	$ 2,523	$ 2,661