Loans - Summary of Concentration of Secured and Unsecured Loans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 184,829	$ 162,135
Loans at fair value	$ 7,655	$ 10,769
Concentration risk percentage	100.00%	100.00%
Corporate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 40,135	$ 37,643
Loans at fair value	$ 996	$ 1,609
Concentration risk percentage	100.00%	100.00%
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 28,879	$ 29,000
Loans at fair value	$ 1,146	$ 1,588
Concentration risk percentage	100.00%	100.00%
Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 23,035	$ 24,674
Loans at fair value	$ 4,511	$ 6,185
Concentration risk percentage	100.00%	100.00%
Securities-based
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 16,671	$ 16,652
Concentration risk percentage	100.00%	100.00%
Other collateralized
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 51,702	$ 38,263
Loans at fair value	$ 716	$ 955
Concentration risk percentage	100.00%	100.00%
Installment
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 6,326	$ 3,672
Concentration risk percentage	100.00%	100.00%
Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 15,820	$ 8,212
Concentration risk percentage	100.00%	100.00%
Other
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 2,261	$ 4,019
Loans at fair value	$ 286	$ 432
Concentration risk percentage	100.00%	100.00%
Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 184,829	$ 162,135
Internally rated loans | Corporate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	40,135	37,643
Internally rated loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	28,879	29,000
Internally rated loans | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	23,035	24,674
Internally rated loans | Securities-based
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	16,671	16,652
Internally rated loans | Other collateralized
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	51,702	38,263
Internally rated loans | Installment
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	6,326	3,672
Internally rated loans | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	15,820	8,212
Internally rated loans | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	2,261	4,019
Amortized Cost
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	172,580	143,507
Amortized Cost | Corporate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	36,822	34,663
Amortized Cost | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	26,222	24,267
Amortized Cost | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	18,523	18,389
Amortized Cost | Securities-based
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	16,671	16,652
Amortized Cost | Other collateralized
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	50,473	35,916
Amortized Cost | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	15,820	8,212
Amortized Cost | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	1,723	1,736
Amortized Cost | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	172,580	143,507
Fair Value
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	7,655	10,769
Fair Value | Corporate
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	996	1,609
Fair Value | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	1,146	1,588
Fair Value | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	4,511	6,185
Fair Value | Securities-based
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	0	0
Fair Value | Other collateralized
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	716	955
Fair Value | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	0	0
Fair Value | Other
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	286	432
Fair Value | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	7,655	10,769
Held For Sale
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	4,594	7,859
Held For Sale | Corporate
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	2,317	1,371
Held For Sale | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	1,511	3,145
Held For Sale | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	1	100
Held For Sale | Securities-based
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	0	0
Held For Sale | Other collateralized
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	513	1,392
Held For Sale | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	0	0
Held For Sale | Other
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	252	1,851
Held For Sale | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	$ 4,594	$ 7,859
Loans Receivable | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Concentration risk percentage	100.00%	100.00%
Loans Receivable | Secured | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Concentration risk percentage	79.00%	82.00%
Loans Receivable | Unsecured | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Concentration risk percentage	21.00%	18.00%
Loans Receivable | Investment-Grade | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 66,172	$ 54,874
Concentration risk percentage	100.00%	100.00%
Loans Receivable | Investment-Grade | Internally rated loans | Corporate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 10,200	$ 8,345
Loans Receivable | Investment-Grade | Internally rated loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	5,208	6,283
Loans Receivable | Investment-Grade | Internally rated loans | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	3,710	3,194
Loans Receivable | Investment-Grade | Internally rated loans | Securities-based
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	12,901	13,801
Loans Receivable | Investment-Grade | Internally rated loans | Other collateralized
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	33,093	22,290
Loans Receivable | Investment-Grade | Internally rated loans | Installment
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	0	0
Loans Receivable | Investment-Grade | Internally rated loans | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	0	0
Loans Receivable | Investment-Grade | Internally rated loans | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 1,060	$ 961
Loans Receivable | Investment-Grade | Secured | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Concentration risk percentage	85.00%	85.00%
Loans Receivable | Investment-Grade | Unsecured | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Concentration risk percentage	15.00%	15.00%
Loans Receivable | Investment-Grade | Amortized Cost | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 63,971	$ 50,923
Loans Receivable | Investment-Grade | Fair Value | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	1,735	2,301
Loans Receivable | Investment-Grade | Held For Sale | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	466	1,650
Loans Receivable | Non-Investment- Grade | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 87,079	$ 84,560
Concentration risk percentage	100.00%	100.00%
Loans Receivable | Non-Investment- Grade | Internally rated loans | Corporate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 29,935	$ 29,183
Loans Receivable | Non-Investment- Grade | Internally rated loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	23,536	22,344
Loans Receivable | Non-Investment- Grade | Internally rated loans | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	13,954	16,071
Loans Receivable | Non-Investment- Grade | Internally rated loans | Securities-based
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	764	447
Loans Receivable | Non-Investment- Grade | Internally rated loans | Other collateralized
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	18,291	15,601
Loans Receivable | Non-Investment- Grade | Internally rated loans | Installment
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	0	0
Loans Receivable | Non-Investment- Grade | Internally rated loans | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	0	0
Loans Receivable | Non-Investment- Grade | Internally rated loans | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 599	$ 914
Loans Receivable | Non-Investment- Grade | Secured | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Concentration risk percentage	93.00%	92.00%
Loans Receivable | Non-Investment- Grade | Unsecured | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Concentration risk percentage	7.00%	8.00%
Loans Receivable | Non-Investment- Grade | Amortized Cost | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 79,648	$ 75,179
Loans Receivable | Non-Investment- Grade | Fair Value | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	3,349	4,634
Loans Receivable | Non-Investment- Grade | Held For Sale | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	4,082	4,747
Loans Receivable | Other Metrics/Unrated | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 31,578	$ 22,701
Concentration risk percentage	100.00%	100.00%
Loans Receivable | Other Metrics/Unrated | Internally rated loans | Corporate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 0	$ 115
Loans Receivable | Other Metrics/Unrated | Internally rated loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	135	373
Loans Receivable | Other Metrics/Unrated | Internally rated loans | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	5,371	5,409
Loans Receivable | Other Metrics/Unrated | Internally rated loans | Securities-based
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	3,006	2,404
Loans Receivable | Other Metrics/Unrated | Internally rated loans | Other collateralized
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	318	372
Loans Receivable | Other Metrics/Unrated | Internally rated loans | Installment
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	6,326	3,672
Loans Receivable | Other Metrics/Unrated | Internally rated loans | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	15,820	8,212
Loans Receivable | Other Metrics/Unrated | Internally rated loans | Other
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 602	$ 2,144
Loans Receivable | Other Metrics/Unrated | Secured | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Concentration risk percentage	27.00%	36.00%
Loans Receivable | Other Metrics/Unrated | Unsecured | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Concentration risk percentage	73.00%	64.00%
Loans Receivable | Other Metrics/Unrated | Amortized Cost | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Total loans, gross	$ 28,961	$ 17,405
Loans Receivable | Other Metrics/Unrated | Fair Value | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Loans at fair value	2,571	3,834
Loans Receivable | Other Metrics/Unrated | Held For Sale | Internally rated loans
Financing Receivable, Recorded Investment [Line Items]
Loans held for sale	$ 46	$ 1,462