Components of Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components Of Income Tax Expense (Benefit) [Line Items]
Income tax expense from continuing operations	$ 236,669	$ 226,166	$ 246,475
Income tax expense (benefit) from discontinued operations	0	(467)	11,830
Other comprehensive income (loss)	201,950	284,355	184,305
Tax basis compensation expense (from the exercise of stock options and vesting of restricted stock awards) in excess of amounts recognized for financial reporting purposes	(22,602)	(13,121)	(3,455)
Income tax expense, Total	$ 416,017	$ 496,933	$ 439,155