Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Accounts receivable and unbilled revenues, reserves	$ 113.3	$ 74.5
Common stock, par value	$ 0.01
Common stock, shares authorized	325,000,000
Common stock, shares outstanding	315,683,496	225,517,339