Litigation, Contractual Commitments and Contingent Liabilities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Contingencies And Commitments [Line Items]
Unrecognized tax refund	$ 32.2
Amount of sales tax assessment	27.4
Long term debt interest payment current year	441
Long term debt interest payment year two	1,770
Long term debt interest payment year three	1,774
Long term debt interest payment year four	1,397
Long term debt interest payment year five	1,228
Long term debt interest payment there after	$ 1,783