Regulatory Capital Requirements (Details) $ in Billions	Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Adjusted total assets	$ 4,446	$ 4,552
Risk-weighted assets	1,331	1,357
Total capital (statutory)
Available Capital (Deficit)	(23)	(34)
Minimum Capital Requirement	106	109
Total Capital Requirement (including Buffers)	$ 106	$ 109
Available Capital (Deficit) Ratio	(0.017)	(0.025)
Minimum Capital Ratio Requirement	0.080	0.080
Total Capital Requirement Ratio (including Buffers)	0.080	0.080
Common equity tier 1 capital
Available Capital (Deficit)	$ (60)	$ (74)
Minimum Capital Requirement	60	61
Total Capital Requirement (including Buffers)	$ 141	$ 140
Available Capital (Deficit) Ratio	(0.045)	(0.055)
Minimum Capital Ratio Requirement	0.045	0.045
Total Capital Requirement Ratio (including Buffers)	0.106	0.103
Tier 1 capital
Available Capital (Deficit)	$ (41)	$ (55)
Minimum Capital Requirement	80	81
Total Capital Requirement (including Buffers)	$ 161	$ 160
Available Capital (Deficit) Ratio	(0.031)	(0.041)
Minimum Capital Ratio Requirement	0.060	0.060
Total Capital Requirement Ratio (including Buffers)	0.121	0.118
Adjusted total capital
Available Capital (Deficit)	$ (41)	$ (55)
Minimum Capital Requirement	106	109
Total Capital Requirement (including Buffers)	$ 187	$ 188
Available Capital (Deficit) Ratio	(0.031)	(0.041)
Minimum Capital Ratio Requirement	0.080	0.080
Total Capital Requirement Ratio (including Buffers)	0.140	0.139
Core capital (statutory)
Available Capital (Deficit)	$ (30)	$ (43)
Minimum Capital Requirement	111	114
Total Capital Requirement (including Buffers)	$ 111	$ 114
Available Capital (Deficit) Ratio	(0.007)	(0.009)
Minimum Capital Ratio Requirement	0.025	0.025
Total Capital Requirement Ratio (including Buffers)	0.025	0.025
Tier 1 capital
Available Capital (Deficit)	$ (41)	$ (55)
Minimum Capital Requirement	111	114
Total Capital Requirement (including Buffers)	$ 135	$ 137
Available Capital (Deficit) Ratio	(0.009)	(0.012)
Minimum Capital Ratio Requirement	0.025	0.025
Total Capital Requirement Ratio (including Buffers)	0.030	0.030