XML 18 R5.htm IDEA: XBRL DOCUMENT v3.8.0.1
CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)
$ in Millions
Mar. 31, 2018
Dec. 31, 2017
Statement of Financial Position [Abstract]    
Accounts receivable and accrued unbilled revenues, reserves $ 160.5 $ 143.2
Property, plant, and equipment, accumulated depreciation $ 8,819.8 $ 8,618.5
Common stock, par value (in dollars per share) $ 0.01 $ 0.01
Common stock, shares authorized 325,000,000 325,000,000
Common stock, shares outstanding 315,538,808 315,574,624