Stockholders' Equity and Noncontrolling Interests Preferred and Common Stock (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
Preferred stock shares authorized (in shares)	2,000,000,000.0		2,000,000,000.0
Common stock shares authorized (in shares)	5,000,000,000.0		5,000,000,000.0
Common stock shares issued (in shares)	1,400,000,000		1,400,000,000
Common stock shares outstanding (in shares)	1,400,000,000		1,400,000,000
Total dividends paid on common stock	$ 539	$ 536