Income Tax Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Line Items]
Income Tax Reconciliation, Change in Enacted Tax Rate		$ 6,300,000	$ 9,300,000	$ 6,800,000
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent		3.00%	2.00%
Excess of Financial Reporting Carrying Amount Over the Tax Basis of Investments in Foreign Subsidiaries, Provision Not Practicable		999,600,000.0
Liability for unrecognized tax benefits		10,200,000	15,000,000	86,900,000
Unrecognized Tax Benefits, Interest on Income Taxes Expense		1,100,000	10,400,000	13,100,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued		800,000	1,900,000
Tax Adjustments, Settlements, and Unusual Provisions		(1,400,000)	(11,000,000)	(41,300,000)
Other_Income_From_Tax_Settlement_Pretax		4,000,000		17,500,000
Other_Income_From_Tax_Settlement_Aftertax		2,600,000		11,400,000
Proceeds from Income Tax Refunds	17,500,000		60,400,000
Impact_of_Reinstatement_of_Exemption_of_Active_Finance_Income		900,000
Operating Loss Carryforwards		0	0
Valuation Allowance, Deferred Tax Asset, Change in Amount				4,100,000
Income Taxes Paid, Net		398,100,000	185,000,000	303,500,000
Minimum
Income Taxes [Line Items]
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority		0
Maximum
Income Taxes [Line Items]
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority		$ 8,000,000