Financial Instruments Subject to Off-Balance Sheet Credit Risk - Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions		Sep. 30, 2023	Dec. 31, 2022
Resale agreements
Gross Assets		$ 3,010	$ 12,159
Gross Amounts Offset in the Condensed Consolidated Balance Sheets		0	0
Net Amounts Presented in the Condensed Consolidated Balance Sheets	[1]	3,010	12,159
Counterparty Offsetting		0	0
Collateral		(3,010)	(12,159)
Net Amount		0	0
Securities borrowed
Gross Assets		892	705
Gross Amounts Offset in the Condensed Consolidated Balance Sheets		0	0
Net Amounts Presented in the Condensed Consolidated Balance Sheets		892	705
Counterparty Offsetting		(646)	(331)
Collateral		(244)	(366)
Net Amount		2	8
Interest rate swaps
Total Gross Assets		3,905	12,864
Gross Amounts Offset in the Condensed Consolidated Balance Sheets		0	0
Net Amounts Presented in the Condensed Consolidated Balance Sheets		3,905	12,864
Counterparty Offsetting		(646)	(331)
Collateral		(3,254)	(12,525)
Net Amount		5	8
Repurchase agreements
Gross Liabilities		6,515	4,402
Gross Amounts Offset in the Condensed Consolidated Balance Sheets		0	0
Net Amounts Presented in the Condensed Consolidated Balance Sheets		6,515	4,402
Counterparty Offsetting		0	0
Collateral		(6,515)	(4,402)
Net Amount		0	0
Securities loaned
Gross Liabilities		5,878	4,200
Gross Amounts Offset in the Condensed Consolidated Balance Sheets		0	0
Net Amounts Presented in the Condensed Consolidated Balance Sheets		5,878	4,200
Counterparty Offsetting		(646)	(331)
Collateral		(4,721)	(3,313)
Net Amount		511	556
Secured short-term borrowings
Total	[1]	7,550	4,650
Total Gross Liabilities		13,343	8,602
Gross Amounts Offset in the Condensed Consolidated Balance Sheets		0	0
Net Amounts Presented in the Condensed Consolidated Balance Sheets		13,343	8,602
Counterparty Offsetting		(646)	(331)
Collateral		(12,186)	(7,715)
Net Amount		511	556
Fair value of client securities available to be pledged		90,299	86,775
Available for sale securities, assets pledged	[1]	110,272	147,871
Secured short-term borrowings
Secured short-term borrowings
Gross Liabilities		950
Gross Amounts Offset in the Condensed Consolidated Balance Sheets		0
Total		950
Counterparty Offsetting		0
Collateral		(950)
Net Amount		0
Asset Pledged as Collateral
Secured short-term borrowings
Available for sale securities, assets pledged	[1]	1,773	41
Interest rate swaps | Asset Pledged as Collateral
Secured short-term borrowings
Available for sale securities, assets pledged		180
Securities Sold under Agreements to Repurchase
Secured short-term borrowings
Fair value of collateral pledged in connection with repurchase agreements		7,000	4,600
Resale and Repurchase Agreements
Secured short-term borrowings
Fair value of client securities available to be pledged		3,100	$ 12,300
Interest rate swaps
Interest rate swaps
Gross Assets		3
Gross Amounts Offset in the Condensed Consolidated Balance Sheets		0
Net Amounts Presented in the Condensed Consolidated Balance Sheets		3
Counterparty Offsetting		0
Collateral		0
Net Amount		$ 3

[1] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.