Pension and OPEB - Periodic Cost (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Pension Plans, Defined Benefit [Member]	Sep. 30, 2012 Pension Plans, Defined Benefit [Member]	Sep. 30, 2013 Pension Plans, Defined Benefit [Member]	Sep. 30, 2012 Pension Plans, Defined Benefit [Member]	Sep. 30, 2013 Other Postretirement Benefit Plans, Defined Benefit [Member]	Sep. 30, 2012 Other Postretirement Benefit Plans, Defined Benefit [Member]	Sep. 30, 2013 Other Postretirement Benefit Plans, Defined Benefit [Member]	Sep. 30, 2012 Other Postretirement Benefit Plans, Defined Benefit [Member]	Sep. 30, 2013 Change in Assumptions for Pension Plans [Member] Pension Plans, Defined Benefit [Member] Rate	Jun. 30, 2013 Change in Assumptions for Pension Plans [Member] Pension Plans, Defined Benefit [Member] Rate
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost						$ 4,897	$ 5,527	$ 16,184	$ 15,530	$ 4,849	$ 4,525	$ 14,547	$ 14,291
Interest cost						9,497	9,396	27,249	28,190	29,619	33,687	88,856	102,008
Expected return on plan assets						(13,336)	(11,538)	(38,191)	(34,617)	0	0	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(8,212)	(13,915)	(24,635)	(39,937)		(408)	(408)	(1,223)	(1,223)	(7,804)	(13,409)	(23,411)	(38,418)
Amortization of actuarial gain	(21,055)	(26,611)	(69,802)	(79,688)		8,042	11,959	30,764	35,876	17,595	20,255	52,784	60,620
Other Comprehensive Income (Loss), Finalization of Pension and Non-Pension Postretirement Plan Valuation, Net of Tax	6,296		(38,498)			6,296	0	38,498	0	0	0	0	0
Net periodic (benefit) cost	19,139	12,696	83,665	39,751		14,988	14,936	73,281	43,756	44,259	45,058	132,776	138,501
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate														4.80%	4.84%
Pension Contributions								55,272
Defined Benefit Plan, Plan Amendments														21,264
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(24,980)	(7,921)	(113,641)	(75,080)										17,040
Deferred Income Taxes	81,825		81,825		148,104									10,520
Defined Benefit Plan, Benefits Paid												$ 124,504