Summary Of Significant Accounting Policies (Reclassifications Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) before income taxes		$ 163	$ 154,190	$ 163		$ 156,599
Income tax expense		33	(84,878)	33		(85,772)
Net income from discontinued operations		196	69,312	196		70,827
Tax expense (a)		(15,016)	(16,691)	(41,263)		(43,973)
Net income		25,274	100,582	71,736		149,563
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) before income taxes		0	(735)	0		(732)
Income tax expense		0	273	0	[1]	272	[1]
Net income from discontinued operations		0	(462)	0		(460)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax		0	0	0	[1]	3	[1]
Other Comprehensive Loss Reclassification Adjustment From AOCI For Sale Of Securities Before Tax		0	(735)	0	[1]	(735)	[1]
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Total before tax		(377)	(174)	(755)		(344)
Tax expense (a)		132	62	264		121
Net income		(245)	(112)	(491)		(223)
Amortization of net loss	[2]	273	38	546		76
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax	[2]	(3,687)	(1,990)	(7,375)		(3,980)
Adjustment due to effects of regulation	[2]	$ 3,037	$ 1,778	$ 6,074		$ 3,560

[1] These amounts were included as part of net income from discontinued operations (see Note 4 for additional details).

[2] These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (see Note 7 for additional details).