Fair Value (Fair Value Option - Changes in Fair Value) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Loans held for sale | Residential mortgage loans held for sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Gains (losses) - FVO: changes in fair value	$ 8	$ 15
Loans held for sale | Commercial mortgage loans held for sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Gains (losses) - FVO: changes in fair value	(5)	1
Loans
Fair Value, Option, Quantitative Disclosures [Line Items]
Gains (losses) - FVO: changes in fair value	6	4
Other assets
Fair Value, Option, Quantitative Disclosures [Line Items]
Gains (losses) - FVO: changes in fair value	5	(14)
Other liabilities
Fair Value, Option, Quantitative Disclosures [Line Items]
Gains (losses) - FVO: changes in fair value	$ (2)	$ (20)