Fair Value Measurements - Carrying Amounts and Estimated Fair Values for Certain Financial Instruments (Details) - USD ($) $ in Millions		Dec. 31, 2022	Dec. 31, 2021
Financial assets:
Other short-term investments	[1]	$ 8,351	$ 34,572
Held-to-maturity securities	[2]	5	8
Loans and leases held for sale	[3]	1,007	4,415
Total portfolio loans and leases, net		119,286	110,158
Financial liabilities:
Deposits		163,690	169,324
Federal funds purchased		180	281
Other short-term borrowings		4,838	980
Long-term debt	[1]	13,714	11,821
Net Carrying Amount
Financial assets:
Cash		3,466	2,994
Other short-term investments		8,351	34,572
Other securities		874	519
Held-to-maturity securities		5	8
Loans and leases held for sale		407	3,392
Total portfolio loans and leases, net		119,163	110,004
Financial liabilities:
Deposits		163,690	169,324
Federal funds purchased		180	281
Other short-term borrowings		4,838	980
Long-term debt		13,778	11,425
Net Carrying Amount | Commercial
Financial assets:
Total portfolio loans and leases, net		75,262	69,166
Net Carrying Amount | Consumer
Financial assets:
Total portfolio loans and leases, net		43,901	40,838
Total Fair Value
Financial assets:
Cash		3,466	2,994
Other short-term investments		8,351	34,572
Other securities		874	519
Held-to-maturity securities		5	8
Loans and leases held for sale		414	3,405
Total portfolio loans and leases, net		117,297	111,556
Financial liabilities:
Deposits		163,634	169,316
Federal funds purchased		180	281
Other short-term borrowings		4,829	980
Long-term debt		13,629	12,478
Total Fair Value | Commercial
Financial assets:
Total portfolio loans and leases, net		75,104	69,924
Total Fair Value | Consumer
Financial assets:
Total portfolio loans and leases, net		42,193	41,632
Total Fair Value | Level 1
Financial assets:
Cash		3,466	2,994
Other short-term investments		8,351	34,572
Other securities		0	0
Held-to-maturity securities		0	0
Loans and leases held for sale		0	0
Total portfolio loans and leases, net		0	0
Financial liabilities:
Deposits		0	0
Federal funds purchased		180	281
Other short-term borrowings		0	0
Long-term debt		13,218	12,091
Total Fair Value | Level 1 | Commercial
Financial assets:
Total portfolio loans and leases, net		0	0
Total Fair Value | Level 1 | Consumer
Financial assets:
Total portfolio loans and leases, net		0	0
Total Fair Value | Level 2
Financial assets:
Cash		0	0
Other short-term investments		0	0
Other securities		874	519
Held-to-maturity securities		0	0
Loans and leases held for sale		0	0
Total portfolio loans and leases, net		0	0
Financial liabilities:
Deposits		163,634	169,316
Federal funds purchased		0	0
Other short-term borrowings		4,829	980
Long-term debt		411	387
Total Fair Value | Level 2 | Commercial
Financial assets:
Total portfolio loans and leases, net		0	0
Total Fair Value | Level 2 | Consumer
Financial assets:
Total portfolio loans and leases, net		0	0
Total Fair Value | Level 3
Financial assets:
Cash		0	0
Other short-term investments		0	0
Other securities		0	0
Held-to-maturity securities		5	8
Loans and leases held for sale		414	3,405
Total portfolio loans and leases, net		117,297	111,556
Financial liabilities:
Deposits		0	0
Federal funds purchased		0	0
Other short-term borrowings		0	0
Long-term debt		0	0
Total Fair Value | Level 3     | Commercial
Financial assets:
Total portfolio loans and leases, net		75,104	69,924
Total Fair Value | Level 3     | Consumer
Financial assets:
Total portfolio loans and leases, net		$ 42,193	$ 41,632

[1] Includes $17 and $24 of other short-term investments, $185 and $322 of portfolio loans and leases, $(2) and $(2) of ALLL, $2 and $2 of other assets, $9 and $1 of other liabilities and $118 and $263 of long-term debt from consolidated VIEs that are included in their respective captions above at December 31, 2022 and 2021, respectively. For further information, refer to Note 12.

[2] Fair value of $5 and $8 at December 31, 2022 and 2021, respectively.

[3] Includes $600 and $1,023 of residential mortgage loans held for sale measured at fair value at December 31, 2022 and 2021, respectively.