Income per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	14	13	14	13
Net income (loss)	$ (170)	$ (386)	$ (577)	$ (662)
Weighted average common shares outstanding, basic	848	677	790	676
Weighted average common shares outstanding, diluted	848	677	790	676
Basic:
Net income (loss), per basic share	$ (0.20)	$ (0.57)	$ (0.73)	$ (0.98)
Diluted:
Net income (loss), per diluted share	$ (0.20)	$ (0.57)	$ (0.73)	$ (0.98)