Summary of Capped Call (Equity Options) Issued (Detail) (Capped call (equity options), USD $) In Millions, except Share data											1 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended
	Jul. 02, 2011 Maximum	Jul. 02, 2011 Maximum Series - I	Jul. 02, 2011 Maximum Series I	Jul. 02, 2011 Maximum Series II	Jul. 02, 2011 Maximum Series III	Jul. 02, 2011 Minimum	Jul. 02, 2011 Minimum Series - I	Jul. 02, 2011 Minimum Series I	Jul. 02, 2011 Minimum Series II	Jul. 02, 2011 Minimum Series III	Nov. 30, 2010	Jul. 02, 2011	May 31, 2011 Series - I	Jul. 02, 2011 Series - I	Jul. 02, 2011 Series I	Jul. 02, 2011 Series II	Jul. 02, 2011 Series III
Option Indexed to Issuer's Equity [Line Items]
Original Number of Options											8,433,123	8,433,123	2,448,588	2,448,588	2,811,041	2,811,041	2,811,041
Net Premium Paid											$ 50.3	$ 50.3	$ 19.6	$ 19.6	$ 16.8	$ 16.8	$ 16.7
Adjusted Strike Price	$ 97.81	$ 80.35	$ 97.81	$ 97.81	$ 97.81	$ 74.86	$ 70.16	$ 74.86	$ 74.86	$ 74.86