Short-Term Borrowings - Outstanding and Weighted-Average Interest Rates of Short-Term Borrowings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Short-term Debt [Line Items]
Weighted-average interest rate as of year-end	4.49%	5.03%
Securities Sold Under Repurchase Agreements
Short-term Debt [Line Items]
Balance as of December 31	$ 841	$ 3,681
Average outstanding during the year	$ 2,198	$ 3,163
Weighted-average interest rate as of year-end	0.73%	5.62%
Weighted-average interest rate during the year	4.32%	4.93%
Other
Short-term Debt [Line Items]
Balance as of December 31	$ 3,750	$ 9,815
Average outstanding during the year	$ 9,396	$ 11,128
Weighted-average interest rate as of year-end	4.33%	4.77%
Weighted-average interest rate during the year	4.62%	5.19%