Total Equity and Other Comprehensive Income (Dividends per Share) (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Sep. 01, 2020
Class of Stock [Line Items]
Common stock held in treasury at cost (shares)	118,000,000		118,000,000		119,000,000
Common Stock
Class of Stock [Line Items]
Cash dividends declared, Common, per share (in dollars per share)	$ 1.15	$ 1.15	$ 2.30	$ 2.30
Series B
Class of Stock [Line Items]
Cash dividends declared, Preferred, per share (in dollars per share)	0.45	0.45	0.90	0.90
Series O
Class of Stock [Line Items]
Cash dividends declared, Preferred, per share (in dollars per share)			3,375	3,375
Series P
Class of Stock [Line Items]
Cash dividends declared, Preferred, per share (in dollars per share)	1,532	1,532	3,063	3,063
Series Q
Class of Stock [Line Items]
Cash dividends declared, Preferred, per share (in dollars per share)		1,344		2,688
Treasury stock, preferred (shares)						4,800
Series R
Class of Stock [Line Items]
Cash dividends declared, Preferred, per share (in dollars per share)	2,425	2,425	2,425	2,425
Series S
Class of Stock [Line Items]
Cash dividends declared, Preferred, per share (in dollars per share)	$ 2,500	$ 2,500	$ 2,500	$ 2,500
Depositary Shares
Class of Stock [Line Items]
Common stock held in treasury at cost (shares)						19,200,000