Reclassification Out of Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Accumulated Net Unrealized Investment Gain (Loss)	Dec. 31, 2012 Accumulated Net Unrealized Investment Gain (Loss)	Mar. 31, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Dec. 31, 2012 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Mar. 31, 2013 Accumulated Defined Benefit Plans Adjustment	Dec. 31, 2012 Accumulated Defined Benefit Plans Adjustment	Mar. 31, 2013 Reclassification Out of Accumulated Other Comprehensive Income Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Mar. 31, 2013 Foreign Exchange Contract Reclassification Out of Accumulated Other Comprehensive Income Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	Mar. 31, 2013 Unrealized Gain (Loss) Reclassification Out of Accumulated Other Comprehensive Income Accumulated Net Unrealized Investment Gain (Loss)	Mar. 31, 2013 Unrealized Gain on Investments Reclassification Out of Accumulated Other Comprehensive Income Accumulated Net Unrealized Investment Gain (Loss)
Reclassification out of Accumulated Other Comprehensive Income
Investment income	$ 33,163	$ 29,452									$ 5,865
Product sales revenue	3,111,936	3,068,857								10,021
Cost of product sales	(1,355,985)	(1,301,550)								(3,879)
Total net gain on derivatives before tax									6,142
Provision for income tax	(76,060)	(190,910)	(36,000)	(36,600)	66,900	67,200	87,300	87,300	(768)			(2,104)
Net of tax									$ 5,374		$ 3,761