Fair Value Measurement - Nonrecurring Basis (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	$ 62,255		$ 70,684
Equity securities adjusted based on the measurement alternative	5,797	$ 3,988	$ 4,900
Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	2,065	1,435
Other assets	428	264
Total assets measured at fair value	2,493	1,699
Accounts payable and other liabilities	129	1
Total liabilities measured at fair value	129	1
Total nonrecurring fair value gains/(losses)	(39)	(48)
Nonrecurring | Accounts payable and other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total nonrecurring fair value gains/(losses)	(129)	(1)
Nonrecurring | Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total nonrecurring fair value gains/(losses)	(39)	(74)
Nonrecurring | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total nonrecurring fair value gains/(losses)	129	27
Nonrecurring | Other assets using measurement alternative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total nonrecurring fair value gains/(losses)	121	34
Nonrecurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
Other assets	0	0
Total assets measured at fair value	0	0
Accounts payable and other liabilities	0	0
Total liabilities measured at fair value	0	0
Nonrecurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	1,594	994
Other assets	3	6
Total assets measured at fair value	1,597	1,000
Accounts payable and other liabilities	0	0
Total liabilities measured at fair value	0	0
Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	471	441
Other assets	425	258
Total assets measured at fair value	896	699
Accounts payable and other liabilities	129	1
Total liabilities measured at fair value	129	$ 1
Equity securities adjusted based on the measurement alternative	$ 373