Pension and Post-Retirement Benefit Plans (Net Periodic Costs And Pension Contributions) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015		Jun. 30, 2014
Components of Net Periodic Cost (Benefit):
Pension Contributions					$ 19,400		$ 19,000
Pension Benefits [Member]
Components of Net Periodic Cost (Benefit):
Service cost	$ 5,348		$ 4,055		10,696		8,110
Interest cost	10,753		10,400		21,507		20,800
Expected return on plan assets	(10,059)		(9,109)		(20,118)		(18,219)
Prior service costs	130		131		260		262
Actuarial loss, net	8,053		4,840		15,714		9,681
Net periodic cost before regulatory adjustment	14,225		10,317		28,059		20,634
Regulatory adjustment	1,534	[1]	4,002	[1]	3,332	[2]	8,003	[2]
Net periodic cost	15,759		14,319		31,391		28,637
Post-Retirement Benefits [Member]
Components of Net Periodic Cost (Benefit):
Service cost	361		345		722		691
Interest cost	1,422		1,588		2,845		3,175
Expected return on plan assets	(1,654)		(1,644)		(3,307)		(3,288)
Prior service costs	114		631		227		1,262
Actuarial loss, net	95		(185)		190		(371)
Net periodic cost before regulatory adjustment	338		735		677		1,469
Regulatory adjustment	1,013	[1]	1,124	[1]	2,026	[2]	2,247	[2]
Net periodic cost	$ 1,351		$ 1,859		$ 2,703		$ 3,716

[1] The regulatory adjustment represents the difference between current period pension or post-retirement benefit expense and the amount of such expense recognized in setting our prices.

[2] (a) The regulatory adjustment represents the difference between current period pension or post-retirement benefit expense and the amount of such expense recognized in setting our prices.