Capital Transactions	12 Months Ended
Dec. 31, 2016
Equity [Abstract]
Capital Transactions	Capital Transactions Repurchase Programs On February 2, 2017, our Board of Directors authorized a new stock repurchase program under which we are authorized to repurchase up to $1 billion of our common stock during the two-year period from February 13, 2017 through February 12, 2019. On February 3, 2015, our Board of Directors authorized a stock repurchase program under which we were authorized to repurchase up to $750 million of our common stock during the two-year period from February 9, 2015 through February 8, 2017. There were no repurchases pursuant to this program. Dividends On February 2, 2017, our Board of Directors approved a cash dividend of $0.30 per common share. Such dividend is payable on May 10, 2017, to shareholders of record at the close of business on March 30, 2017. On February 2, 2016, our Board of Directors declared a cash dividend of $0.26 per common share. Such dividend was payable on May 11, 2016, to shareholders of record at the close of business on March 30, 2016. On May 11, 2016, we made an aggregate cash dividend payment of $192 million to such shareholders, and on May 27, 2016, we made related dividend equivalent payments of $3 million to certain holders of restricted stock rights. On February 3, 2015, our Board of Directors declared a cash dividend of $0.23 per common share. Such dividend was payable on May 13, 2015, to shareholders of record at the close of business on March 30, 2015. On May 13, 2015, we made an aggregate cash dividend payment of $167 million to such shareholders, and on May 29, 2015, we made related dividend equivalent payments of $3 million to certain holders of restricted stock rights. On February 6, 2014, our Board of Directors declared a cash dividend of $0.20 per common share. Such dividend was payable on May 14, 2014, to shareholders of record at the close of business on March 19, 2014. On May 14, 2014, we made an aggregate cash dividend payment of $143 million to such shareholders, and on May 30, 2014, we made related dividend equivalent payments of $4 million to the holders of restricted stock rights.

Capital Transactions

Repurchase Programs

On February 2, 2017, our Board of Directors authorized a new stock repurchase program under which we are authorized to repurchase up to $1 billion of our common stock during the two-year period from February 13, 2017 through February 12, 2019.

On February 3, 2015, our Board of Directors authorized a stock repurchase program under which we were authorized to repurchase up to $750 million of our common stock during the two-year period from February 9, 2015 through February 8, 2017. There were no repurchases pursuant to this program.

Dividends

On February 2, 2017, our Board of Directors approved a cash dividend of $0.30 per common share. Such dividend is payable on May 10, 2017, to shareholders of record at the close of business on March 30, 2017.

On February 2, 2016, our Board of Directors declared a cash dividend of $0.26 per common share. Such dividend was payable on May 11, 2016, to shareholders of record at the close of business on March 30, 2016. On May 11, 2016, we made an aggregate cash dividend payment of $192 million to such shareholders, and on May 27, 2016, we made related dividend equivalent payments of $3 million to certain holders of restricted stock rights.

On February 3, 2015, our Board of Directors declared a cash dividend of $0.23 per common share. Such dividend was payable on May 13, 2015, to shareholders of record at the close of business on March 30, 2015. On May 13, 2015, we made an aggregate cash dividend payment of $167 million to such shareholders, and on May 29, 2015, we made related dividend equivalent payments of $3 million to certain holders of restricted stock rights.

On February 6, 2014, our Board of Directors declared a cash dividend of $0.20 per common share. Such dividend was payable on May 14, 2014, to shareholders of record at the close of business on March 19, 2014. On May 14, 2014, we made an aggregate cash dividend payment of $143 million to such shareholders, and on May 30, 2014, we made related dividend equivalent payments of $4 million to the holders of restricted stock rights.