Capital Stock	12 Months Ended
Dec. 31, 2017
Equity [Abstract]
CAPITAL STOCK	CAPITAL STOCK Stock Repurchase Programs The Company’s Board of Directors authorized an ongoing stock repurchase program with a total repurchase authority granted to the Company of $8.5 billion, of which $500.0 million was approved in January 2017 and an additional $1.7 billion was approved in November 2017. The Company may use the approved dollar authority to repurchase stock at any time until the approved amount is exhausted. The objective of the Company’s stock repurchase program is to improve stockholders’ returns. At December 31, 2017, approximately $1.43 billion was available to repurchase common stock pursuant to the stock repurchase program. All shares repurchased are recorded as treasury stock. A portion of the funds used to repurchase stock over the course of the program was provided by net proceeds from the Convertible Notes offering, as well as proceeds from employee stock option exercises and the related tax benefit. The Company is authorized to make open market purchases of its common stock using general corporate funds through open market purchases, pursuant to a Rule 10b5-1 plan or in privately negotiated transactions. During the year ended December 31, 2017, the Company expended approximately $575.0 million on open market purchases under the stock repurchase program, repurchasing 7,384,368 shares of outstanding common stock at an average price of $77.86. In addition to the repurchases described above, the Company used the net proceeds from the 2027 Notes offering to repurchase an aggregate of approximately $750.0 million of shares of its common stock as authorized under the Company's share repurchase program. The Company paid $750.0 million to Citibank N.A. (the "ASR Counterparty") under the Accelerated Share Repurchase ("ASR") agreement and received approximately 7.1 million shares of its common stock from the ASR Counterparty, which represents 80 percent of the shares pursuant to the ASR agreement. The total number of shares of common stock that the Company will repurchase under the ASR agreement will be based on the average of the daily volume-weighted average prices of the common stock during the term of the ASR agreement, less a discount. At settlement, the ASR Counterparty may be required to deliver additional shares of the Company’s common stock to the Company or, under certain circumstances, the Company may be required to deliver shares of its common stock or make a cash payment to the ASR Counterparty. Final settlement of the ASR agreement was completed in January 2018 and the Company received delivery of 1,371,495 additional shares of its common stock. During the year ended December 31, 2016, the Company expended approximately $28.7 million on open market purchases under the stock repurchase program, repurchasing 426,300 shares of outstanding common stock at an average price of $67.30. During the year ended December 31, 2015, the Company expended approximately $755.7 million on open market purchases under the stock repurchase program, repurchasing 10,716,850 shares of outstanding common stock at an average price of $70.52. Shares for Tax Withholding During the years ended December 31, 2017, 2016 and 2015, the Company withheld 974,501 shares, 830,155 shares and 679,694 shares, respectively, from equity awards that vested. Amounts withheld to satisfy minimum tax withholding obligations that arose on the vesting of equity awards was $80.0 million, $66.6 million and $46.3 million, for 2017, 2016 and 2015, respectively. These shares are reflected as treasury stock in the Company's consolidated balance sheets and the related cash outlays do not reduce the Company's total stock repurchase authority. Preferred Stock The Company is authorized to issue 5,000,000 shares of preferred stock, $0.01 par value per share. No shares of such preferred stock were issued and outstanding at December 31, 2017 or 2016.

CAPITAL STOCK

Stock Repurchase Programs

The Company’s Board of Directors authorized an ongoing stock repurchase program with a total repurchase authority granted to the Company of $8.5 billion, of which $500.0 million was approved in January 2017 and an additional $1.7 billion was approved in November 2017. The Company may use the approved dollar authority to repurchase stock at any time until the approved amount is exhausted. The objective of the Company’s stock repurchase program is to improve stockholders’ returns. At December 31, 2017, approximately $1.43 billion was available to repurchase common stock pursuant to the stock repurchase program. All shares repurchased are recorded as treasury stock. A portion of the funds used to repurchase stock over the course of the program was provided by net proceeds from the Convertible Notes offering, as well as proceeds from employee stock option exercises and the related tax benefit. The Company is authorized to make open market purchases of its common stock using general corporate funds through open market purchases, pursuant to a Rule 10b5-1 plan or in privately negotiated transactions.

During the year ended December 31, 2017, the Company expended approximately $575.0 million on open market purchases under the stock repurchase program, repurchasing 7,384,368 shares of outstanding common stock at an average price of $77.86.

In addition to the repurchases described above, the Company used the net proceeds from the 2027 Notes offering to repurchase an aggregate of approximately $750.0 million of shares of its common stock as authorized under the Company's share repurchase program. The Company paid $750.0 million to Citibank N.A. (the "ASR Counterparty") under the Accelerated Share Repurchase ("ASR") agreement and received approximately 7.1 million shares of its common stock from the ASR Counterparty, which represents 80 percent of the shares pursuant to the ASR agreement. The total number of shares of common stock that the Company will repurchase under the ASR agreement will be based on the average of the daily volume-weighted average prices of the common stock during the term of the ASR agreement, less a discount. At settlement, the ASR Counterparty may be required to deliver additional shares of the Company’s common stock to the Company or, under certain circumstances, the Company may be required to deliver shares of its common stock or make a cash payment to the ASR Counterparty. Final settlement of the ASR agreement was completed in January 2018 and the Company received delivery of 1,371,495 additional shares of its common stock.

During the year ended December 31, 2016, the Company expended approximately $28.7 million on open market purchases under the stock repurchase program, repurchasing 426,300 shares of outstanding common stock at an average price of $67.30.

During the year ended December 31, 2015, the Company expended approximately $755.7 million on open market purchases under the stock repurchase program, repurchasing 10,716,850 shares of outstanding common stock at an average price of $70.52.

Shares for Tax Withholding

During the years ended December 31, 2017, 2016 and 2015, the Company withheld 974,501 shares, 830,155 shares and 679,694 shares, respectively, from equity awards that vested. Amounts withheld to satisfy minimum tax withholding obligations that arose on the vesting of equity awards was $80.0 million, $66.6 million and $46.3 million, for 2017, 2016 and 2015, respectively. These shares are reflected as treasury stock in the Company's consolidated balance sheets and the related cash outlays do not reduce the Company's total stock repurchase authority.

Preferred Stock

The Company is authorized to issue 5,000,000 shares of preferred stock, $0.01 par value per share. No shares of such preferred stock were issued and outstanding at December 31, 2017 or 2016.