Fair Value Measurements - Carrying Amounts and Estimated Fair Values for Certain Financial Instruments (Details) - USD ($) $ in Millions		Sep. 30, 2022	Dec. 31, 2021
Financial assets:
Cash and due from banks		$ 3,068	$ 2,994
Other short-term investments	[1]	6,594	34,572
Held-to-maturity securities		5	8
Loans and leases held for sale	[2]	1,940	4,415
Total portfolio loans and leases, net		117,900	110,158
Financial liabilities:
Deposits		161,652	169,324
Federal funds purchased		212	281
Other short-term borrowings		6,378	980
Long-term debt	[1]	11,712	11,821
Commercial
Financial assets:
Total portfolio loans and leases, net		75,778	70,268
Consumer
Financial assets:
Total portfolio loans and leases, net		44,221	41,782
Net Carrying Amount
Financial assets:
Cash and due from banks		3,068	2,994
Other short-term investments		6,594	34,572
Other securities		874	519
Held-to-maturity securities		5	8
Loans and leases held for sale		833	3,392
Total portfolio loans and leases, net		117,775	110,004
Financial liabilities:
Deposits		161,652	169,324
Federal funds purchased		212	281
Other short-term borrowings		6,378	980
Long-term debt		11,808	11,425
Net Carrying Amount | Commercial
Financial assets:
Total portfolio loans and leases, net		74,620	69,166
Net Carrying Amount | Consumer
Financial assets:
Total portfolio loans and leases, net		43,155	40,838
Total Fair Value
Financial assets:
Cash and due from banks		3,068	2,994
Other short-term investments		6,594	34,572
Other securities		874	519
Held-to-maturity securities		5	8
Loans and leases held for sale		837	3,405
Total portfolio loans and leases, net		114,909	111,556
Financial liabilities:
Deposits		161,606	169,316
Federal funds purchased		212	281
Other short-term borrowings		6,365	980
Long-term debt		11,435	12,478
Total Fair Value | Commercial
Financial assets:
Total portfolio loans and leases, net		74,090	69,924
Total Fair Value | Consumer
Financial assets:
Total portfolio loans and leases, net		40,819	41,632
Total Fair Value | Level 1
Financial assets:
Cash and due from banks		3,068	2,994
Other short-term investments		6,594	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		212	281
Other short-term borrowings		0	0
Long-term debt		11,032	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 and due from banks		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		161,606	169,316
Federal funds purchased		0	0
Other short-term borrowings		6,365	980
Long-term debt		403	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 and due from banks		0	0
Other short-term investments		0	0
Other securities		0	0
Held-to-maturity securities		5	8
Loans and leases held for sale		837	3,405
Total portfolio loans and leases, net		114,909	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		74,090	69,924
Total Fair Value | Level 3 | Consumer
Financial assets:
Total portfolio loans and leases, net		$ 40,819	$ 41,632

[1] Includes $19 and $24 of other short-term investments, $223 and $322 of portfolio loans and leases, $(3) and $(2) of ALLL, $2 and $2 of other assets, $9 and $1 of other liabilities, and $156 and $263 of long-term debt from consolidated VIEs that are included in their respective captions above at September 30, 2022 and December 31, 2021, respectively. For further information, refer to Note 12.

[2] Includes $1,107 and $1,023 of residential mortgage loans held for sale measured at fair value at September 30, 2022 and December 31, 2021, respectively.