Interim Pension and Other Postretirement Benefits (Details) (USD $)	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Pension Plans Defined Benefit [Member]
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate			5.05%	5.68%
Rate of compensation increase			3.50%	4.00%
Expected return on plan assets			7.75%	8.25%
Components of net periodic pension cost [Abstract]
Service Cost	$ 4,298,000	$ 4,257,000	$ 8,596,000	$ 8,637,000
Interest Cost	6,678,000	7,055,000	13,355,000	13,979,000
Expected return on assets	5,369,000	6,285,000	10,737,000	12,248,000
Amortization of transition asset	0	0	0	0
Amortization of prior service cost	(36,000)	(105,000)	(71,000)	(217,000)
Recognized actuarial loss	(4,143,000)	(2,748,000)	(8,285,000)	(6,242,000)
Curtailment Loss	0	40,000	0	40,000
Defined Benefit Plan Net Periodic Benefit Cost	9,714,000	7,630,000	19,428,000	16,353,000
Current Year Benefit Plan Contributions [Abstract]
Contributions Actual			34,200,000
Contributions Estimate	12,400,000		12,400,000
Other Postretirement Benefit Plans Defined Benefit [Member]
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate			5.05%	5.39%
Expected return on plan assets			4.70%	5.00%
Components of net periodic pension cost [Abstract]
Service Cost	4,088,000	3,601,000	8,176,000	7,202,000
Interest Cost	3,466,000	3,203,000	6,931,000	6,406,000
Expected return on assets	652,000	682,000	1,304,000	1,364,000
Amortization of transition asset	378,000	378,000	756,000	756,000
Amortization of prior service cost	(363,000)	(363,000)	(725,000)	(725,000)
Recognized actuarial loss	(662,000)	(86,000)	(1,324,000)	(173,000)
Curtailment Loss	0	0	0	0
Defined Benefit Plan Net Periodic Benefit Cost	7,579,000	6,223,000	15,158,000	12,448,000
Current Year Benefit Plan Contributions [Abstract]
Contributions Actual			9,100,000
Contributions Estimate Minimum	10,000,000		10,000,000
Contributions Estimate Maximum	$ 15,000,000		$ 15,000,000
Other Pension Plans Defined Benefit [Member]
Defined Benefit Plan Weighted Average Assumptions Used In Calculating Net Periodic Benefit Cost Abstract
Discount Rate			5.05%	5.39%
Rate of compensation increase			3.50%	4.00%
Expected return on plan assets			7.75%	8.25%