Equity (Preferred Stock Dividends) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Class of Stock [Line Items]
Preferred stock, aggregate dividends declared	$ 26	$ 27	$ 21	$ 25	$ 53	$ 46
6.600% Non-Cumulative Preferred Stock, Series A
Class of Stock [Line Items]
Preferred stock, dividends declared per share	$ 412.50		$ 412.50		$ 825.00	$ 825.00
Preferred stock, aggregate dividends declared	$ 7		$ 7		$ 14	$ 14
6.750% Non-Cumulative Preferred Stock, Series B
Class of Stock [Line Items]
Preferred stock, dividends declared per share	$ 421.88		$ 421.88		$ 843.76	$ 843.76
Preferred stock, aggregate dividends declared	$ 7		$ 7		$ 14	$ 14
5.375% Non-Cumulative Preferred Stock, Series C
Class of Stock [Line Items]
Preferred stock, dividends declared per share	$ 335.94		$ 335.94		$ 671.88	$ 802.52
Preferred stock, aggregate dividends declared	$ 8		$ 7		$ 16	$ 18
4.625% Non-Cumulative Preferred Stock, Series D
Class of Stock [Line Items]
Preferred stock, dividends declared per share	$ 289.06		$ 0		$ 684.11	$ 0
Preferred stock, aggregate dividends declared	$ 4		$ 0		$ 9	$ 0