Shareholders' Equity - Schedule of Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Dividends Payable [Line Items]
Preferred stock cash dividend	$ 20	$ 34	$ 25	$ 38	$ 32	$ 44	$ 79	$ 114
Series C Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)							$ 0	$ 1,313
Preferred stock cash dividend							$ 0	$ 6
Series C Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)							$ 0	$ 0.33
Series D Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 1,475			$ 1,475			$ 4,425	$ 4,425
Preferred stock cash dividend	$ 11			$ 11			$ 33	$ 33
Series D Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0.37			$ 0.37			$ 1.11	$ 1.11
Series F Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 950			$ 2,625			$ 2,869	$ 5,250
Preferred stock cash dividend	$ 2			$ 20			$ 11	$ 40
Series F Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 9.50			$ 26.25			$ 28.69	$ 52.50
Series G Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 1,338			$ 1,338			$ 4,014	$ 4,014,000,000
Preferred stock cash dividend	$ 7			$ 7			$ 21	$ 21
Series G Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0.33			$ 0.33			$ 0.99	$ 0.99
Series H Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0			$ 0			$ 2,813	$ 2,813
Preferred stock cash dividend	$ 0			$ 0			$ 14	$ 14
Series H Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0			$ 0			$ 28.13	$ 28.13