Stockholders' Equity (Notes)	9 Months Ended
Sep. 30, 2018
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	— Stockholders’ Equity Share Repurchase Program On May 2, 2018, the Company announced that our Board of Directors authorized a Share Repurchase Program (the “Repurchase Program”) to repurchase up to $500 million of our common stock. On August 10, 2018, the Company announced that our Board of Directors increased its share repurchase authorization to $750 million of our common stock. Repurchases may be made at the Company’s discretion from time to time on the open market or in privately negotiated transactions. The Repurchase Program has no time limit, does not obligate the Company to make any repurchases, and may be suspended for periods or discontinued at any time. Any shares acquired are available for general corporate purposes. During the three and nine months ended September 30, 2018, we repurchased approximately 28 million shares and 31 million shares, respectively, for approximately $280 million and $311 million, respectively, under the program recorded in Treasury stock.

Stockholders' Equity (Notes)

9 Months Ended

Sep. 30, 2018

Stockholders' Equity Attributable to Parent [Abstract]

Stockholders' Equity Note Disclosure [Text Block]

— Stockholders’ Equity

Share Repurchase Program

On May 2, 2018, the Company announced that our Board of Directors authorized a Share Repurchase Program (the “Repurchase Program”) to repurchase up to $500 million of our common stock. On August 10, 2018, the Company announced that our Board of Directors increased its share repurchase authorization to $750 million of our common stock. Repurchases may be made at the Company’s discretion from time to time on the open market or in privately negotiated transactions. The Repurchase Program has no time limit, does not obligate the Company to make any repurchases, and may be suspended for periods or discontinued at any time. Any shares acquired are available for general corporate purposes. During the three and nine months ended September 30, 2018, we repurchased approximately 28 million shares and 31 million shares, respectively, for approximately $280 million and $311 million, respectively, under the program recorded in Treasury stock.