Revenue from Contracts with Customers (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		$ 188	$ 189	$ 373	$ 373
Other sources of noninterest income		59	61	111	115
Total noninterest income		247	250	484	488
Commercial Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		104	93	193	185
Other sources of noninterest income		40	43	78	87
Total noninterest income		144	136	271	272
Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		21	31	49	60
Other sources of noninterest income		3	2	3	4
Total noninterest income		24	33	52	64
Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		63	65	131	128
Other sources of noninterest income		3	3	5	4
Total noninterest income		66	68	136	132
Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0	0	0
Other sources of noninterest income		13	13	25	20
Total noninterest income		13	13	25	20
Credit and Debit Card [Member]
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		68	65	127	128
Credit and Debit Card [Member] | Commercial Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		59	54	108	107
Credit and Debit Card [Member] | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		8	10	17	19
Credit and Debit Card [Member] | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		1	1	2	2
Credit and Debit Card [Member] | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0	0	0
Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		42	51	91	102
Service charges on deposit accounts | Commercial Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		30	33	62	66
Service charges on deposit accounts | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		11	17	27	34
Service charges on deposit accounts | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		1	1	2	2
Service charges on deposit accounts | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0	0	0
Fiduciary income
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		52	52	106	101
Fiduciary income | Commercial Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0	0	0
Fiduciary income | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0	0	0
Fiduciary income | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		52	52	106	101
Fiduciary income | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0	0	0
Commercial loan servicing fees
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	4	4	8	8
Commercial loan servicing fees | Commercial Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	4	4	8	8
Commercial loan servicing fees | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	0	0	0	0
Commercial loan servicing fees | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	0	0	0	0
Commercial loan servicing fees | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	0	0	0	0
Brokerage Commissions Revenue [Member]
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		5	7	12	14
Brokerage Commissions Revenue [Member] | Commercial Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0	0	0
Brokerage Commissions Revenue [Member] | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0	0	0
Brokerage Commissions Revenue [Member] | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		5	7	12	14
Brokerage Commissions Revenue [Member] | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0	0	0
Other noninterest income
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	17	10	29	20
Other noninterest income | Commercial Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	11	2	15	4
Other noninterest income | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	2	4	5	7
Other noninterest income | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	4	4	9	9
Other noninterest income | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	$ 0	$ 0	$ 0	$ 0

[1] Included in commercial lending fees on the Consolidated Statements of Comprehensive Income.

[2] Excludes derivative, warrant and other miscellaneous income.