Stockholders' Equity - Earnings per Share (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity [Abstract]
As reported shares (in shares)	998	934	996	925
Effect of options and performance share award units (in shares)	7	6	7	6
Diluted shares (in shares)	1,005	940	1,003	931
Stock options and performance share award units that were not included in the diluted earnings per share calculation (in shares)	0	0	0	0