Shareholders' Equity - Schedule of Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Dividends Payable [Line Items]
Preferred stock cash dividend	$ 34	$ 25	$ 32	$ 44	$ 59	$ 76
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		$ 2,950	$ 2,950
Preferred stock cash dividend	$ 11		$ 11		$ 22	$ 22
Series D Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0.37		$ 0.37		$ 0.74	$ 0.74
Series F Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 966		$ 0		$ 1,919	$ 2,625
Preferred stock cash dividend	$ 2		$ 0		$ 9	$ 20
Series F Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 9.66		$ 0		$ 19.19	$ 26.25
Series G Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 1,338		$ 1,338		$ 2,676	$ 2,676,000,000
Preferred stock cash dividend	$ 7		$ 7		$ 14	$ 14
Series G Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 0.33		$ 0.33		$ 0.66	$ 0.66
Series H Preferred Stock
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 2,813		$ 2,813		$ 2,813	$ 2,813
Preferred stock cash dividend	$ 14		$ 14		$ 14	$ 14
Series H Preferred Stock, Depository Share
Dividends Payable [Line Items]
Preferred dividends declared (USD per share)	$ 28.13		$ 28.13		$ 28.13	$ 28.13