Stockholders' Equity Schedule of Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividends, Preferred Stock		$ 9	$ 14
Preferred Stock, Dividend Rate, Per-Dollar-Amount		$ 1.333	$ 2
Dividends, Common Stock	$ 964	$ 777	$ 763
Common Stock, Dividends, Per Share, Cash Paid	$ 2.16	$ 2.16	$ 2.3
Preferred Class B [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividends, Preferred Stock	$ 14	$ 14	$ 14
Preferred Stock, Dividend Rate, Per-Dollar-Amount	$ 1.9375	$ 1.9375	$ 1.9375
Series C Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividends, Preferred Stock	$ 23	$ 9
Preferred Stock, Dividend Rate, Per-Dollar-Amount	$ 1.75	$ 0.69514