Revenue from Contracts with Customers (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		$ 185	$ 184
Other sources of noninterest income		52	54
Total noninterest income		237	238
Business Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		89	92
Other sources of noninterest income		38	44
Total noninterest income		127	136
Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		28	29
Other sources of noninterest income		0	2
Total noninterest income		28	31
Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		68	63
Other sources of noninterest income		2	1
Total noninterest income		70	64
Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0
Other sources of noninterest income		12	7
Total noninterest income		12	7
Credit and Debit Card [Member]
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		59	63
Credit and Debit Card [Member] | Business Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		49	53
Credit and Debit Card [Member] | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		9	9
Credit and Debit Card [Member] | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		1	1
Credit and Debit Card [Member] | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0
Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		49	51
Service charges on deposit accounts | Business Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		32	33
Service charges on deposit accounts | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		16	17
Service charges on deposit accounts | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		1	1
Service charges on deposit accounts | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0
Fiduciary income
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		54	49
Fiduciary income | Business Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0
Fiduciary income | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0
Fiduciary income | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		54	49
Fiduciary income | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0
Commercial loan servicing fees
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	4	4
Commercial loan servicing fees | Business Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	4	4
Commercial loan servicing fees | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	0	0
Commercial loan servicing fees | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	0	0
Commercial loan servicing fees | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[1]	0	0
Brokerage Commissions Revenue [Member]
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		7	7
Brokerage Commissions Revenue [Member] | Business Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0
Brokerage Commissions Revenue [Member] | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0
Brokerage Commissions Revenue [Member] | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		7	7
Brokerage Commissions Revenue [Member] | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers		0	0
Other noninterest income
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	12	10
Other noninterest income | Business Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	4	2
Other noninterest income | Retail Bank
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	3	3
Other noninterest income | Wealth Management
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	5	5
Other noninterest income | Finance & Other
Segment Reporting, Revenue Reconciling Item
Total revenue from contracts with customers	[2]	$ 0	$ 0

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

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