Fair Value Measurement - Transfers (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, liabilities	$ 229	$ 793	$ 103
Transfers from level 3 into level 2, liabilities	729	1,044	809
Realized/unrealized gains (losses), liabilities	(3,010)	3,869	(369)
Non-trading loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets	1,306	1,053	1,301
Transfers from Level 3 into level 2, assets	1,065	831	794
Realized/unrealized gains (losses), assets	289	(158)	(87)
Total debt and equity instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets	728	2,445	1,000
Transfers from Level 3 into level 2, assets	1,100	1,188	1,428
Realized/unrealized gains (losses), assets	0	(1,082)	(33)
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets	192	1,066	164
Transfers from Level 3 into level 2, assets	218	121	111
Realized/unrealized gains (losses), assets	(53)	(1,036)	(77)
Trading loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets	382	925	648
Transfers from Level 3 into level 2, assets	529	640	873
Realized/unrealized gains (losses), assets	(15)	(51)	2
Recurring | Derivative payables | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, liabilities	2,100	878
Transfers from level 3 into level 2, liabilities		807
Recurring | Derivative payables | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, liabilities	829	2,300	1,200
Transfers from level 3 into level 2, liabilities	1,700	2,300	2,100
Recurring | Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, liabilities		793
Transfers from level 3 into level 2, liabilities		1,000	809
Recurring | Derivative receivables | Interest rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets	951	1,600
Transfers from Level 3 into level 2, assets	921	1,200
Recurring | Derivative receivables | Equity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets	1,500	1,600	1,500
Transfers from Level 3 into level 2, assets	2,300	2,200	1,900
Recurring | Non-trading loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets	1,300	1,100	1,300
Transfers from Level 3 into level 2, assets	1,100	831	794
Recurring | Total debt and equity instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets		2,400	1,000
Transfers from Level 3 into level 2, assets	1,100	1,200	1,400
Recurring | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets		1,100
Recurring | Trading loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers from level 2 into level 3, assets		925
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Realized/unrealized gains (losses), assets	1,800	7,700	495
Realized/unrealized gains (losses), liabilities	$ (3,300)	$ 4,600	$ 1,100