Capital Stock - Conditional Restricted Stock (Detail) (Conditional Restricted Stock [Member], USD $)	12 Months Ended
	Dec. 31, 2012
Conditional Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Shares, nonvested, Beginning Balance, Shares	1,019,000
Granted, Shares	852,000
Vested, Shares	(1,000)
Forfeited or cancelled, Shares	(564,000)
Restricted Shares, nonvested, Ending Balance, Shares	1,306,000
Non-vested at January 1, 2012, Weighted Average Grant Date Fair Value	$ 115.10
Granted, Weighted Average Grant-Date Fair Value	$ 70.30
Vested, Weighted Average Grant-Date Fair Value	$ 100.81
Forfeited, Weighted Average Grant-Date Fair Value	$ 132.45
Non-vested at December 31, 2012, Weighted Average Grant Date Fair Value	$ 78.40