Assets Measured at Fair Value on a Nonrecurring Basis (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment charges			$ 16.6	$ 19.6
Fair Value, Measurements, Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets held and used, impairment charge	3.2	0.6	4.4	5.2
Long-lived assets held for sale or disposal, impairment charge	5.4	0.9	12.6	14.9
Impairment charges	8.6	1.5	17.0	20.1
Long-lived assets held and used, net book value	4.4	3.9	4.4	3.9
Long-lived assets held for sale or disposal, net book value	17.1	5.4	17.1	5.4
Total	21.5	9.3	21.5	9.3
Fair Value, Measurements, Nonrecurring | Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets held and used, fair value measurement	3.7	1.2	4.6	4.6
Long-lived assets held for sale or disposal, fair value measurement	5.2		18.8	5.4
Total, Fair value measurement	$ 8.9	$ 1.2	$ 23.4	$ 10.0