Loans and Related Allowance for Credit Losses (Home Equity and Residential Real Estate Credit Quality Indicators) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net	[1]	$ 318,416		$ 318,416		$ 326,025
Gross charge-offs
Total		233	$ 222	808	$ 668
Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		4,442		4,442		10,594
Year two		10,192		10,192		16,650
Year three		15,695		15,695		7,392
Year four		6,945		6,945		2,482
Year five		2,310		2,310		878
Prior		7,775		7,775		7,893
Total loans, net		47,359		47,359		45,889
Gross charge-offs
Year two				1
Year four				1
Prior				4
Total				6
Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year two						180
Year three		168		168		2,143
Year four		1,971		1,971		997
Year five		897		897		291
Prior		2,723		2,723		2,897
Revolving Loans		8,461		8,461		8,902
Revolving Loans Converted to Term		11,939		11,939		10,573
Total loans, net		26,159		26,159		25,983
Gross charge-offs
Prior				2
Revolving Loans				4
Revolving Loans Converted to Term				9
Total				15
Greater than or equal to 780 | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		2,418		2,418		6,825
Year two		7,728		7,728		12,596
Year three		12,239		12,239		5,276
Year four		5,060		5,060		1,623
Year five		1,538		1,538		463
Prior		4,099		4,099		4,027
Total loans, net		33,082		33,082		30,810
Greater than or equal to 780 | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year two						110
Year three		107		107		1,357
Year four		1,283		1,283		554
Year five		503		503		155
Prior		1,685		1,685		1,791
Revolving Loans		4,700		4,700		5,093
Revolving Loans Converted to Term		6,039		6,039		5,545
Total loans, net		14,317		14,317		14,605
720 to 779 | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		1,495		1,495		3,172
Year two		1,857		1,857		3,024
Year three		2,547		2,547		1,369
Year four		1,214		1,214		476
Year five		414		414		180
Prior		1,439		1,439		1,457
Total loans, net		8,966		8,966		9,678
720 to 779 | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year two						47
Year three		38		38		515
Year four		443		443		248
Year five		223		223		64
Prior		525		525		567
Revolving Loans		2,203		2,203		2,305
Revolving Loans Converted to Term		3,193		3,193		2,843
Total loans, net		6,625		6,625		6,589
660 to 719 | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		302		302		514
Year two		514		514		744
Year three		670		670		378
Year four		322		322		189
Year five		176		176		98
Prior		782		782		796
Total loans, net		2,766		2,766		2,719
660 to 719 | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year two						19
Year three		18		18		211
Year four		185		185		140
Year five		117		117		42
Prior		286		286		288
Revolving Loans		1,210		1,210		1,146
Revolving Loans Converted to Term		1,756		1,756		1,449
Total loans, net		3,572		3,572		3,295
Less than 660 | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		86		86		63
Year two		64		64		108
Year three		129		129		110
Year four		110		110		88
Year five		87		87		71
Prior		676		676		740
Total loans, net		1,152		1,152		1,180
Less than 660 | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year two						4
Year three		5		5		57
Year four		58		58		54
Year five		53		53		29
Prior		219		219		242
Revolving Loans		338		338		342
Revolving Loans Converted to Term		895		895		671
Total loans, net		1,568		1,568		1,399
No FICO score available | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		132		132		11
Year two		11		11		163
Year three		92		92		193
Year four		173		173		67
Year five		58		58		38
Prior		275		275		337
Total loans, net		741		741		809
No FICO score available | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year three						3
Year four		2		2		1
Year five		1		1		1
Prior		8		8		9
Revolving Loans		10		10		16
Revolving Loans Converted to Term		56		56		65
Total loans, net		77		77		95
Government insured or guaranteed loans | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		9		9		9
Year two		18		18		15
Year three		18		18		66
Year four		66		66		39
Year five		37		37		28
Prior		504		504		536
Total loans, net		652		652		693
Greater than 100% | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		34		34		4
Year two		141		141		52
Year three		103		103		20
Year four		33		33		10
Year five		8		8		4
Prior		34		34		41
Total loans, net		353		353		131
Greater than 100% | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year two						4
Year three		2		2		14
Year four		10		10		9
Year five		5		5		2
Prior		13		13		15
Revolving Loans		294		294		268
Revolving Loans Converted to Term		285		285		137
Total loans, net		609		609		449
Greater than or equal to 80% to 100% | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		1,770		1,770		1,185
Year two		3,372		3,372		678
Year three		1,044		1,044		232
Year four		207		207		84
Year five		69		69		24
Prior		105		105		92
Total loans, net		6,567		6,567		2,295
Greater than or equal to 80% to 100% | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year two						4
Year three		5		5		51
Year four		39		39		27
Year five		21		21		4
Prior		27		27		31
Revolving Loans		1,266		1,266		854
Revolving Loans Converted to Term		1,949		1,949		1,149
Total loans, net		3,307		3,307		2,120
Less than 80% | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		2,577		2,577		9,396
Year two		6,661		6,661		15,844
Year three		14,517		14,517		7,074
Year four		6,639		6,639		2,346
Year five		2,196		2,196		822
Prior		7,129		7,129		7,220
Total loans, net		39,719		39,719		42,702
Less than 80% | Home equity
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year two						172
Year three		161		161		2,078
Year four		1,922		1,922		961
Year five		871		871		285
Prior		2,683		2,683		2,851
Revolving Loans		6,901		6,901		7,780
Revolving Loans Converted to Term		9,705		9,705		9,287
Total loans, net		22,243		22,243		23,414
No LTV available | Residential real estate
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Year one		52		52
Year two						61
Year three		13		13
Year four						3
Prior		3		3		4
Total loans, net		$ 68		$ 68		$ 68

[1] Our consolidated assets included the following for which we have elected the fair value option: Loans held for sale of $0.9 billion, Loans held for investment of $1.2 billion and Other assets of $0.1 billion at September 30, 2023. Comparable amounts at December 31, 2022 were $0.9 billion, $1.3 billion and $0.1 billion, respectively.