Earnings per Common Share (Schedule of Basic and Diluted Earnings per Common Share) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	$ 261	$ 273	$ 865	$ 621
Dividends, Preferred Stock, Cash	0	(38)	(30)	(1,356)
Net income (loss) from continuing operations attributable to common shareholders	261	235	835	(735)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(52)	(5)	(46)	405
Net Income (Loss) Available to Common Stockholders, Basic	$ 209	$ 230	$ 789	$ (330)
Weighted Average Number of Shares Outstanding, Basic	482,392,811	483,073,329	483,992,930	482,725,342
Weighted Average Number of Shares Outstanding, Diluted	483,575,307	484,399,091	484,762,142	482,725,342
Stock Repurchase and Redemption Premium				$ 1,193
Earnings Per Share, Basic [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.54	$ 0.49	$ 1.73	$ (1.52)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	(0.11)	(0.01)	(0.10)	0.84
Earnings Per Share, Basic	0.43	0.48	1.63	(0.68)
Earnings Per Share, Diluted [Abstract]
Income (Loss) from Continuing Operations, Per Diluted Share	0.54	0.49	1.72	(1.52)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	(0.11)	(0.01)	(0.10)	0.84
Earnings Per Share, Diluted	$ 0.43	$ 0.47	$ 1.63	$ (0.68)