Accumulated Other Comprehensive Income Reclassifications in AOCI (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income (Loss) from Continuing Operations before Income Taxes									$ 942,172	$ 585,169	$ 401,432
Provision for income taxes									(331,747)	(199,614)	(142,466)
Other income, net									6,790	3,520	5,628
Net income	170,972	170,290	145,816	123,347	95,277	86,964	115,501	87,813	610,425	385,555	258,966
Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net income									(1,681)
Amortization of pension and other post-retirement items | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior service costs									(381)
Net loss									(2,331)
Income (Loss) from Continuing Operations before Income Taxes									(2,712)
Provision for income taxes									1,043
Net income									(1,669)
Net unrealized gains on available-for-sale investments | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Provision for income taxes									7
Other income, net									(19)
Net income									$ (12)