Common Stock	6 Months Ended
Jun. 30, 2018
Equity [Abstract]
Common Stock	Common Stock During the first six months of 2018, the Company repurchased approximately 6.1 million shares of its common stock for consideration of $500 million. In November 2016, the Board of Directors of the Company authorized the Company to repurchase up to $2.5 billion in shares of the Company's common stock, which superseded any prior authorizations. As of June 30, 2018, the Company remained authorized to repurchase up to approximately $1 billion in shares of its common stock. There is no time limit on the authorization. During the first six months of 2017, the Company repurchased approximately 5.4 million shares of its common stock for consideration of $400 million. The Company issued approximately 2.5 million and 3.7 million shares related to stock compensation and employee stock purchase plans during the first six months of 2018 and 2017, respectively.

Common Stock

6 Months Ended

Jun. 30, 2018

During the first six months of 2018, the Company repurchased approximately 6.1 million shares of its common stock for consideration of $500 million. In November 2016, the Board of Directors of the Company authorized the Company to repurchase up to $2.5 billion in shares of the Company's common stock, which superseded any prior authorizations. As of June 30, 2018, the Company remained authorized to repurchase up to approximately $1 billion in shares of its common stock. There is no time limit on the authorization. During the first six months of 2017, the Company repurchased approximately 5.4 million shares of its common stock for consideration of $400 million.

The Company issued approximately 2.5 million and 3.7 million shares related to stock compensation and employee stock purchase plans during the first six months of 2018 and 2017, respectively.