Capital Stock	6 Months Ended
Jun. 30, 2017
Equity [Abstract]
Capital Stock	Capital Stock Treasury Stock In August 1998, the Board of Directors authorized a share repurchase program under which the Company may purchase shares of common stock in the open market or in negotiated transactions. The timing and amount of any stock purchases are determined at the discretion of management. The Company may use the repurchased shares to fund stock compensation programs currently in existence, or for other corporate purposes. All purchases executed to date have been through open market transactions. There is no expiration date associated with the authorization to repurchase common stock of the Company. During the first six months of 2017, the Company repurchased 3.0 million shares for a total cost of $68.3 million. Since the authorization date, the Company has repurchased 32.9 million shares of the 40.0 million total shares authorized for a total cost of approximately $456.6 million, of which 20.0 million shares have been retired. No treasury shares have been delivered or sold by the Company subsequent to the repurchase. As of June 30, 2017, 12.9 million shares were held as treasury stock.

Capital Stock

6 Months Ended

Jun. 30, 2017

Treasury Stock

In August 1998, the Board of Directors authorized a share repurchase program under which the Company may purchase shares of common stock in the open market or in negotiated transactions. The timing and amount of any stock purchases are determined at the discretion of management. The Company may use the repurchased shares to fund stock compensation programs currently in existence, or for other corporate purposes. All purchases executed to date have been through open market transactions. There is no expiration date associated with the authorization to repurchase common stock of the Company.

During the first six months of 2017, the Company repurchased 3.0 million shares for a total cost of $68.3 million. Since the authorization date, the Company has repurchased 32.9 million shares of the 40.0 million total shares authorized for a total cost of approximately $456.6 million, of which 20.0 million shares have been retired. No treasury shares have been delivered or sold by the Company subsequent to the repurchase. As of June 30, 2017, 12.9 million shares were held as treasury stock.