Loans and Related Allowance for Credit Losses (Home Equity and Residential Real Estate Credit Quality Indicators) (Details) - USD ($) $ in Millions		Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	[1]	$ 294,457	$ 288,372
Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one		3,408	16,961
Year two		17,026	8,473
Year three		8,022	3,114
Year four		2,789	1,133
Year five		1,023	1,688
Prior		9,298	8,343
Total loans		41,566	39,712
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			212
Year two		197	2,588
Year three		2,412	1,265
Year four		1,160	386
Year five		351	562
Prior		3,524	3,291
Revolving Loans		8,717	9,187
Revolving Loans Converted to Term		7,824	6,570
Total loans		24,185	24,061
Greater than or equal to 780 | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one		1,551	11,110
Year two		11,744	5,898
Year three		5,524	1,996
Year four		1,780	596
Year five		531	1,029
Prior		4,681	4,052
Total loans		25,811	24,681
Greater than or equal to 780 | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			124
Year two		117	1,619
Year three		1,488	692
Year four		622	201
Year five		183	364
Prior		2,159	2,035
Revolving Loans		5,208	5,490
Revolving Loans Converted to Term		4,162	3,320
Total loans		13,939	13,845
720 to 779 | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one		1,712	4,921
Year two		4,217	1,735
Year three		1,678	643
Year four		566	247
Year five		219	345
Prior		1,820	1,619
Total loans		10,212	9,510
720 to 779 | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			61
Year two		54	666
Year three		629	348
Year four		321	96
Year five		81	116
Prior		700	642
Revolving Loans		2,160	2,283
Revolving Loans Converted to Term		1,995	1,679
Total loans		5,940	5,891
660 to 719 | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one		142	717
Year two		812	463
Year three		456	255
Year four		226	136
Year five		127	133
Prior		906	796
Total loans		2,669	2,500
660 to 719 | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			23
Year two		23	248
Year three		236	167
Year four		161	56
Year five		53	53
Prior		360	327
Revolving Loans		1,015	1,071
Revolving Loans Converted to Term		983	872
Total loans		2,831	2,817
Less than 660 | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one		1	83
Year two		113	103
Year three		104	96
Year four		105	75
Year five		75	94
Prior		901	848
Total loans		1,299	1,299
Less than 660 | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			4
Year two		3	53
Year three		56	57
Year four		55	32
Year five		33	28
Prior		295	277
Revolving Loans		315	325
Revolving Loans Converted to Term		608	615
Total loans		1,365	1,391
No FICO score available | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one		2	127
Year two		136	241
Year three		225	87
Year four		77	49
Year five		44	48
Prior		378	359
Total loans		862	911
No FICO score available | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year two			2
Year three		3	1
Year four		1	1
Year five		1	1
Prior		10	10
Revolving Loans		19	18
Revolving Loans Converted to Term		76	84
Total loans		110	117
Government insured or guaranteed loans | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			3
Year two		4	33
Year three		35	37
Year four		35	30
Year five		27	39
Prior		612	669
Total loans		713	811
Greater than 100% | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			10
Year two		30	52
Year three		56	21
Year four		16	12
Year five		10	13
Prior		61	77
Total loans		173	185
Greater than 100% | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			1
Year two		1	16
Year three		19	14
Year four		12	3
Year five		3	2
Prior		25	25
Revolving Loans		319	329
Revolving Loans Converted to Term		101	90
Total loans		480	480
Greater than or equal to 80% to 100% | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one		780	1,460
Year two		659	560
Year three		497	221
Year four		176	86
Year five		75	66
Prior		216	190
Total loans		2,403	2,583
Greater than or equal to 80% to 100% | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			7
Year two		6	85
Year three		84	62
Year four		51	13
Year five		9	11
Prior		58	66
Revolving Loans		838	990
Revolving Loans Converted to Term		830	674
Total loans		1,876	1,908
Less than 80% | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one		2,628	15,213
Year two		16,282	7,822
Year three		7,422	2,834
Year four		2,562	1,004
Year five		910	1,570
Prior		8,395	7,385
Total loans		38,199	35,828
Less than 80% | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			204
Year two		190	2,487
Year three		2,309	1,189
Year four		1,097	370
Year five		339	549
Prior		3,441	3,200
Revolving Loans		7,560	7,868
Revolving Loans Converted to Term		6,893	5,806
Total loans		21,829	21,673
No LTV available | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Year one			275
Year two		51	6
Year three		12	1
Year four			1
Year five		1
Prior		14	22
Total loans		$ 78	$ 305

[1] Our consolidated assets included the following for which we have elected the fair value option: Loans held for sale of $1.3 billion, Loans held for investment of $1.4 billion and Other assets of $0.1 billion at March 31, 2022. Comparable amounts at December 31, 2021 were $1.9 billion, $1.5 billion and $0.1 billion, respectively.