Stock Repurchases	12 Months Ended
Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Stock Repurchases	Stock Repurchases: Our Board of Directors has authorized a total of $2 billion towards the repurchase of shares of our common stock (collectively referred to as the "Share Repurchase Plans"), including a $550 million share repurchase authorization in 2016. The Share Repurchase Plans authorize open market repurchase transactions and do not have a stated expiration date. As of December 31, 2016, $646.0 million of shares may still be repurchased under the Share Repurchase Plans. On February 10, 2016, the Company entered into a Fixed Dollar Accelerated Share Repurchase Transaction (the “First ASR Agreement”) with Merrill Lynch International (“Merrill Lynch”), acting through its agent, Merrill Lynch, Pierce, Fenner and Smith Incorporated to effect an accelerated stock buyback of the Company’s common stock (the “Common Stock”). Under the First ASR Agreement, on February 10, 2016, the Company paid Merrill Lynch an initial purchase price of $200.0 million, and Merrill Lynch delivered to the Company a total of 1.3 million shares of Common Stock, representing approximately 75% of the shares expected to be purchased under the ASR Agreement. The First ASR Agreement was completed in the third quarter and Merrill Lynch delivered an additional 0.2 million shares of Common Stock to the Company. On August 1, 2016, the Company entered into another Fixed Dollar ASR Agreement (the "Second ASR Agreement) with Wells Fargo to effect an accelerated stock buyback of Common Stock. Under the Second ASR Agreement, on August 1, 2016, the Company paid Wells Fargo an initial purchase price of $100.0 million, and Wells Fargo delivered to the Company a total of 0.5 million shares of Common Stock, representing approximately 75% of the shares expected to be purchased under the Second ASR Agreement. The Second ASR Agreement was completed in the fourth quarter and Wells Fargo delivered an additional 0.2 million shares of Common Stock to the Company. We also repurchased 0.2 million shares for $33.3 million and 0.3 million shares for $32.0 million for the years ended December 31, 2016 and 2015, respectively, from employees who surrendered their shares to satisfy minimum tax withholding obligations upon the vesting of stock-based compensation awards.

Stock Repurchases:

Our Board of Directors has authorized a total of $2 billion towards the repurchase of shares of our common stock (collectively referred to as the "Share Repurchase Plans"), including a $550 million share repurchase authorization in 2016. The Share Repurchase Plans authorize open market repurchase transactions and do not have a stated expiration date. As of December 31, 2016, $646.0 million of shares may still be repurchased under the Share Repurchase Plans.

On February 10, 2016, the Company entered into a Fixed Dollar Accelerated Share Repurchase Transaction (the “First ASR Agreement”) with Merrill Lynch International (“Merrill Lynch”), acting through its agent, Merrill Lynch, Pierce, Fenner and Smith Incorporated to effect an accelerated stock buyback of the Company’s common stock (the “Common Stock”).

Under the First ASR Agreement, on February 10, 2016, the Company paid Merrill Lynch an initial purchase price of $200.0 million, and Merrill Lynch delivered to the Company a total of 1.3 million shares of Common Stock, representing approximately 75% of the shares expected to be purchased under the ASR Agreement. The First ASR Agreement was completed in the third quarter and Merrill Lynch delivered an additional 0.2 million shares of Common Stock to the Company.

On August 1, 2016, the Company entered into another Fixed Dollar ASR Agreement (the "Second ASR Agreement) with Wells Fargo to effect an accelerated stock buyback of Common Stock.

Under the Second ASR Agreement, on August 1, 2016, the Company paid Wells Fargo an initial purchase price of $100.0 million, and Wells Fargo delivered to the Company a total of 0.5 million shares of Common Stock, representing approximately 75% of the shares expected to be purchased under the Second ASR Agreement. The Second ASR Agreement was completed in the fourth quarter and Wells Fargo delivered an additional 0.2 million shares of Common Stock to the Company.

We also repurchased 0.2 million shares for $33.3 million and 0.3 million shares for $32.0 million for the years ended December 31, 2016 and 2015, respectively, from employees who surrendered their shares to satisfy minimum tax withholding obligations upon the vesting of stock-based compensation awards.