Loans, Lending Commitments and Related Allowance for Credit Losses - Modified Loans Held for Investment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 107	$ 385	$ 422	$ 503
Percent of total loans	0.00%	0.20%	0.20%	0.30%
Term Extension
Financing Receivable, Modified [Line Items]
Amortized Cost			$ 421	$ 463
Percent of total loans			0.20%	0.30%
Multiple Modifications - [Term Extension and Other-than-insignificant Payment Delay]
Financing Receivable, Modified [Line Items]
Amortized Cost			$ 1	$ 40
Percent of total loans			0.00%	0.50%
Modified Terms
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 212	$ 424	$ 676	$ 877
Corporate | Term Extension
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 30	$ 82	$ 136	$ 114
Percent of total loans	0.50%	1.10%	2.20%	1.60%
Corporate | Term Extension | Single Modifications
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification	11 months	23 months	23 months	21 months
Corporate | Other-than-insignificant Payment Delay | Single Modifications
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification	0 months	0 months	0 months	0 months
Corporate | Principal Forgiveness | Single Modifications
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 0	$ 0	$ 0	$ 0
Corporate | Interest Rate Reduction | Single Modifications
Financing Receivable, Modified [Line Items]
Percent of total loans	0.00%	0.00%	0.00%	0.00%
Commercial real estate | Single Modifications
Financing Receivable, Modified [Line Items]
Percent of total loans	0.00%
Commercial real estate | Multiple Modifications - Term Extension and Other-than-insignificant Payment Delay
Financing Receivable, Modified [Line Items]
Percent of total loans				0.00%
Commercial real estate | Term Extension
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 56	$ 198	$ 136	$ 219
Percent of total loans	0.60%	2.40%	1.60%	2.60%
Commercial real estate | Term Extension | Single Modifications
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification	27 months	3 months	14 months	3 months
Commercial real estate | Term Extension | Multiple Modifications - Term Extension and Other-than-insignificant Payment Delay
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification				7 months
Commercial real estate | Multiple Modifications - [Term Extension and Other-than-insignificant Payment Delay]
Financing Receivable, Modified [Line Items]
Amortized Cost			$ 0	$ 40
Percent of total loans			0.00%	0.50%
Commercial real estate | Other-than-insignificant Payment Delay | Single Modifications
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification	0 months	0 months	0 months	0 months
Commercial real estate | Other-than-insignificant Payment Delay | Multiple Modifications - Term Extension and Other-than-insignificant Payment Delay
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification				6 months
Commercial real estate | Principal Forgiveness | Single Modifications
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 0	$ 0	$ 0	$ 0
Commercial real estate | Principal Forgiveness | Multiple Modifications - Term Extension and Other-than-insignificant Payment Delay
Financing Receivable, Modified [Line Items]
Amortized Cost				$ 0
Commercial real estate | Interest Rate Reduction | Single Modifications
Financing Receivable, Modified [Line Items]
Percent of total loans		0.00%	0.00%	0.00%
Residential real estate | Term Extension
Financing Receivable, Modified [Line Items]
Amortized Cost			$ 0	$ 1
Percent of total loans			0.00%	0.00%
Residential real estate | Term Extension | Single Modifications
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification				4 months
Residential real estate | Term Extension | Multiple Modifications - Term Extension and Other-than-insignificant Payment Delay
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification			120 months
Residential real estate | Multiple Modifications - [Term Extension and Other-than-insignificant Payment Delay]
Financing Receivable, Modified [Line Items]
Amortized Cost			$ 1	$ 0
Percent of total loans			0.00%	0.00%
Residential real estate | Other-than-insignificant Payment Delay | Single Modifications
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification				0 months
Residential real estate | Other-than-insignificant Payment Delay | Multiple Modifications - Term Extension and Other-than-insignificant Payment Delay
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification			0 months
Residential real estate | Principal Forgiveness | Single Modifications
Financing Receivable, Modified [Line Items]
Amortized Cost				$ 0
Residential real estate | Principal Forgiveness | Multiple Modifications - Term Extension and Other-than-insignificant Payment Delay
Financing Receivable, Modified [Line Items]
Amortized Cost			$ 0
Residential real estate | Interest Rate Reduction | Single Modifications
Financing Receivable, Modified [Line Items]
Percent of total loans				0.00%
Residential real estate | Interest Rate Reduction | Multiple Modifications - Term Extension and Other-than-insignificant Payment Delay
Financing Receivable, Modified [Line Items]
Percent of total loans			1.00%
Securities-based lending and Other | Term Extension
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 21	$ 105	$ 149	$ 129
Percent of total loans	0.00%	0.10%	0.20%	0.10%
Securities-based lending and Other | Term Extension | Single Modifications
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification	12 months	4 months	21 months	8 months
Securities-based lending and Other | Other-than-insignificant Payment Delay | Single Modifications
Financing Receivable, Modified [Line Items]
Weighted average term increase from modification	0 months	0 months	0 months	0 months
Securities-based lending and Other | Principal Forgiveness | Single Modifications
Financing Receivable, Modified [Line Items]
Amortized Cost	$ 0	$ 0	$ 0	$ 0
Securities-based lending and Other | Interest Rate Reduction | Single Modifications
Financing Receivable, Modified [Line Items]
Percent of total loans	0.00%	0.00%	0.00%	0.00%