Shareholders' Equity	12 Months Ended
Dec. 31, 2018
Equity [Abstract]
Shareholders' Equity	Shareholders' Equity During the fourth and third quarters of 2018, we declared a cash dividend on our common stock of $0.70 per share which was paid in the first quarter of 2019 and fourth quarter of 2018, respectively. During the first and second quarters of 2018, we declared a cash dividend on our common stock of $0.60 per share which was paid in the second and third quarters of 2018, respectively. During the fourth and third quarters of 2017, we declared a cash dividend on our common stock of $0.60 per share which was paid in the first quarter of 2018 and fourth quarter of 2017, respectively. During the first and second quarters of 2017, we declared a cash dividend on our common stock of $0.48 per share which was paid in the second and third quarters of 2017, respectively. During the first quarter of 2017, we also paid a cash dividend on our common stock of $0.48 per share which was declared during the fourth quarter of 2016. In May 2018, our board of directors authorized a 24-month common stock repurchase program for up to $1.0 billion. The timing and number of shares to be repurchased will depend on a variety of factors, including price and market conditions. Repurchases under the program may be made at management's discretion from time to time on the open market or through privately negotiated transactions. During the year ended December 31, 2018, we repurchased 2.8 million shares of our common stock under this program, for a total of $300.0 million, in open market transactions that were recorded within Treasury stock in our consolidated balance sheets. As of December 31, 2018, we have $700.0 million that remains available for future stock repurchase transactions under our Board authorized program. In April 2017, our board of directors authorized a 12-month common stock repurchase program for up to $500.0 million that was completed in February 2018. During 2018 and 2017, we repurchased 2.1 million and 1.8 million shares of our common stock for a total of $275.0 million and $225.0 million, respectively, totaling $500.0 million in open market transactions that were recorded within Treasury stock in our consolidated balance sheets.

Shareholders' Equity

During the fourth and third quarters of 2018, we declared a cash dividend on our common stock of $0.70 per share which was paid in the first quarter of 2019 and fourth quarter of 2018, respectively. During the first and second quarters of 2018, we declared a cash dividend on our common stock of $0.60 per share which was paid in the second and third quarters of 2018, respectively.

During the fourth and third quarters of 2017, we declared a cash dividend on our common stock of $0.60 per share which was paid in the first quarter of 2018 and fourth quarter of 2017, respectively. During the first and second quarters of 2017, we declared a cash dividend on our common stock of $0.48 per share which was paid in the second and third quarters of 2017, respectively. During the first quarter of 2017, we also paid a cash dividend on our common stock of $0.48 per share which was declared during the fourth quarter of 2016.

In May 2018, our board of directors authorized a 24-month common stock repurchase program for up to $1.0 billion. The timing and number of shares to be repurchased will depend on a variety of factors, including price and market conditions. Repurchases under the program may be made at management's discretion from time to time on the open market or through privately negotiated transactions. During the year ended December 31, 2018, we repurchased 2.8 million shares of our common stock under this program, for a total of $300.0 million, in open market transactions that were recorded within Treasury stock in our consolidated balance sheets. As of December 31, 2018, we have $700.0 million that remains available for future stock repurchase transactions under our Board authorized program.

In April 2017, our board of directors authorized a 12-month common stock repurchase program for up to $500.0 million that was completed in February 2018. During 2018 and 2017, we repurchased 2.1 million and 1.8 million shares of our common stock for a total of $275.0 million and $225.0 million, respectively, totaling $500.0 million in open market transactions that were recorded within Treasury stock in our consolidated balance sheets.