Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Allowance for doubtful accounts receivable	$ 202.3	$ 216.3
Property and equipment accumulated depreciation	$ 2,681.3	$ 1,991.5
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,250.0	1,250.0
Common stock, shares issued	125.1	125.1
Common stock, shares outstanding	125.1	125.1
Treasury stock, shares	0.3	0.3