Components of Debt (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Debt Disclosure [Line Items]
Other	$ 37.7	[1]	$ 38.4	[1]
Total debt	3,533.8		3,438.6
Less: current portion	(21.6)		(18.4)
Long-term debt	3,512.2		3,420.2
Senior Notes Four Point Nine Five Percent Due April One Two Thousand Fourteen
Debt Disclosure [Line Items]
Senior notes	258.1		258.1
Senior Notes Five Point Five Zero Percent Due May Fifteen Two Thousand Fifteen
Debt Disclosure [Line Items]
Senior notes	299.9		299.9
Senior Notes Eight Point Six Zero Percent due August Fifteen Two Thousand Sixteen
Debt Disclosure [Line Items]
Senior notes	218.4		347.4
Senior Notes Six Point One Two Five Percent Due January Fifteen Two Thousand Seventeen
Debt Disclosure [Line Items]
Senior notes	350.4		523.3
Senior Notes Seven Point Two Five Percent Due May Fifteen Two Thousand Eighteen
Debt Disclosure [Line Items]
Senior notes	550.0		600.0
Senior Notes Eleven Point Two Five Percent Due February One Two Thousand Nineteen
Debt Disclosure [Line Items]
Debentures	172.2	[2]	172.2	[2]
Senior Notes Eight Point Two Five Percent Due March Fifteen Two Thousand Nineteen
Debt Disclosure [Line Items]
Senior notes	450.0		450.0
Senior Notes Seven Point Six Two Five Percent Due June Fifteen Two Thousand Twenty
Debt Disclosure [Line Items]
Senior notes	400.0		400.0
Senior Notes Seven Point Eight Seven Five Percent Due March Fifteen Two Thousand Twenty One
Debt Disclosure [Line Items]
Senior notes	447.8
Debentures Eight Point Eight Seven Five Percent Due April Fifteen Two Thousand Twenty One
Debt Disclosure [Line Items]
Debentures	80.9		80.9
Debentures Six Point Six Two Five Percent Due April Fifteen Two Thousand Twenty Nine
Debt Disclosure [Line Items]
Debentures	199.4		199.4
Debentures Eight Point Eight Two Zero Percent Due April Fifteen Two Thousand Thirty One
Debt Disclosure [Line Items]
Debentures	$ 69.0		$ 69.0

[1] Includes miscellaneous debt obligations, fair value adjustments to the 4.95% senior notes due April 1, 2014 and 8.25% senior notes due March 15, 2019 related to the Company’s fair value hedges and capital leases.

[2] On May 17, 2011, June 14, 2012, August 2, 2012 and September 20, 2012, the interest rate on the 11.25% senior notes due February 1, 2019 was increased to 11.75%, 12.0%, 12.25% and 12.50%, respectively, as a result of downgrades in the ratings of the notes by the rating agencies.