Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	$ 22,984	$ 22,984	$ 30,913
Derivative Assets	314	314	285
Derivative Liabilities	274	274	237
Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	14	14	0
Derivative Liabilities	0	0	0
Client interest rate derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	115	115	68
Derivative Liabilities	116	116	27
U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	9,277	9,277	4,470
U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	208	208	237
Foreign government debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	15	15	24
Residential mortgage-backed securities | Agency-issued mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	10,784	10,784	13,503
Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations—fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	1,138	1,138	8,107
Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	1,562	1,562	4,572
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	22,984	22,984	30,913
Total assets	24,100	24,100	31,956
Total liabilities	282	282	237
Recurring | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	8	8
Recurring | Foreign exchange contract | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	185	185	217
Recurring | Foreign exchange contract | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	158	158	210
Recurring | Equity warrant assets | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	274	274	203
Recurring | Interest rate swaps | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	14	14
Recurring | Client interest rate derivatives | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	115	115	68
Recurring | Client interest rate derivatives | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	116	116	27
Other liabilities	8	8
Recurring | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	520	520	555
Recurring | Other securities | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	158	158	281
Recurring | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	9,277	9,277	4,470
Recurring | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	208	208	237
Recurring | Foreign government debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	15	15	24
Recurring | Residential mortgage-backed securities | Agency-issued mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	10,784	10,784	13,503
Recurring | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations—fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	1,138	1,138	8,107
Recurring | Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	1,562	1,562	4,572
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	9,292	9,292	4,494
Total assets	9,343	9,343	4,537
Total liabilities	8	8	0
Recurring | Level 1 | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	8	8
Recurring | Level 1 | Foreign exchange contract | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	0	0
Recurring | Level 1 | Foreign exchange contract | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	0	0	0
Recurring | Level 1 | Equity warrant assets | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	0	0
Recurring | Level 1 | Interest rate swaps | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	0
Recurring | Level 1 | Client interest rate derivatives | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	0	0
Recurring | Level 1 | Client interest rate derivatives | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	0	0	0
Other liabilities	8	8
Recurring | Level 1 | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	43	43	43
Recurring | Level 1 | Other securities | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	43	43	43
Recurring | Level 1 | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	9,277	9,277	4,470
Recurring | Level 1 | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 1 | Foreign government debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	15	15	24
Recurring | Level 1 | Residential mortgage-backed securities | Agency-issued mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 1 | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations—fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 1 | Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	13,692	13,692	26,419
Total assets	14,130	14,130	26,953
Total liabilities	274	274	237
Recurring | Level 2 | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0	0
Recurring | Level 2 | Foreign exchange contract | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	185	185	217
Recurring | Level 2 | Foreign exchange contract | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	158	158	210
Recurring | Level 2 | Equity warrant assets | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	9	9	11
Recurring | Level 2 | Interest rate swaps | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	14	14
Recurring | Level 2 | Client interest rate derivatives | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	115	115	68
Recurring | Level 2 | Client interest rate derivatives | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	116	116	27
Other liabilities	0	0
Recurring | Level 2 | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	115	115	238
Recurring | Level 2 | Other securities | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	115	115	238
Recurring | Level 2 | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 2 | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	208	208	237
Recurring | Level 2 | Foreign government debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 2 | Residential mortgage-backed securities | Agency-issued mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	10,784	10,784	13,503
Recurring | Level 2 | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations—fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	1,138	1,138	8,107
Recurring | Level 2 | Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	1,562	1,562	4,572
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Total assets	265	265	192
Total liabilities	0	0	0
Recurring | Level 3 | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0	0
Recurring | Level 3 | Foreign exchange contract | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	0	0
Recurring | Level 3 | Foreign exchange contract | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	0	0	0
Recurring | Level 3 | Equity warrant assets | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	265	265	192
Recurring | Level 3 | Interest rate swaps | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	0
Recurring | Level 3 | Client interest rate derivatives | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets	0	0	0
Recurring | Level 3 | Client interest rate derivatives | Other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	0	0	0
Other liabilities	0	0
Recurring | Level 3 | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	0	0	0
Recurring | Level 3 | Other securities | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	0	0	0
Recurring | Level 3 | U.S. treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 3 | U.S. agency debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 3 | Foreign government debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 3 | Residential mortgage-backed securities | Agency-issued mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 3 | Residential mortgage-backed securities | Agency-issued collateralized mortgage obligations—fixed rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Level 3 | Agency-issued commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value	0	0	0
Recurring | Measured at net asset value | Consolidated venture capital and private equity fund investments | Fair value accounting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-marketable securities	$ 362	$ 362	$ 274
Lower Limit | Other equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, sales restriction, period	3 years
Lower Limit | Level 3 | Equity warrant asset, public portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, sales restriction, period	3 months
Upper Limit | Other equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, sales restriction, period		6 months
Upper Limit | Level 3 | Equity warrant asset, public portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, sales restriction, period	6 months
Sales restrictions discount | Level 3 | Equity warrant asset, public portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input	0.100	0.100
Sales restrictions discount | Lower Limit | Other equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input	0.10	0.10
Sales restrictions discount | Lower Limit | Level 3 | Equity warrant asset, public portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input	0.10	0.10	0.100
Sales restrictions discount | Upper Limit | Other equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input	0.20	0.20
Sales restrictions discount | Upper Limit | Equity warrant asset, public portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input	0.20	0.20
Sales restrictions discount | Upper Limit | Level 3 | Equity warrant asset, public portfolio
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement input	0.20	0.20	0.200