Total Equity - Preferred Stock Dividends (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Preferred Stock Dividends
Preferred stock dividends declared	$ 113	$ 93	$ 376	$ 356
Series A
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 256	$ 256	$ 758	$ 758
Preferred stock dividends declared	$ 11	$ 11	$ 33	$ 33
Series C
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 25	$ 25	$ 75	$ 75
Preferred stock dividends declared	$ 13	$ 13	$ 39	$ 39
Series E
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 445	$ 445	$ 1,336	$ 1,336
Preferred stock dividends declared	$ 15	$ 15	$ 45	$ 45
Series F
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 430	$ 430	$ 1,289	$ 1,289
Preferred stock dividends declared	$ 15	$ 15	$ 45	$ 45
Series G
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 414	$ 414	$ 1,242	$ 1,242
Preferred stock dividends declared	$ 8	$ 8	$ 24	$ 24
Series H
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 378	$ 0	$ 1,059	$ 681
Preferred stock dividends declared	$ 20	$ 0	$ 55	$ 35
Series I
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 398	$ 398	$ 1,195	$ 1,195
Preferred stock dividends declared	$ 16	$ 16	$ 48	$ 48
Series J
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 0	$ 0	$ 694	$ 694
Preferred stock dividends declared	$ 0	$ 0	$ 42	$ 42
Series K
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 366	$ 366	$ 1,097	$ 1,097
Preferred stock dividends declared	$ 15	$ 15	$ 45	$ 45