Pension and Postretirement Plans (Fair Value of Pension Plan Assets) (Details 10) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	$ 2,469,968	$ 2,371,849
Cash equivalents and other short-term investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	417,046	281,463
U.S. equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	1,454,011	1,383,738
International equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	691,505	699,649
Corporate debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value		5,147
Total investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	2,562,562	2,369,997
Receivables [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	(92,594)	1,852
Level 1 [Member] | Cash equivalents and other short-term investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	275,963	196,757
Level 1 [Member] | U.S. equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	1,454,011	1,383,738
Level 1 [Member] | International equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	691,505	699,649
Level 1 [Member] | Corporate debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value		0
Level 1 [Member] | Total investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	2,421,479	2,280,144
Level 2 [Member] | Cash equivalents and other short-term investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	141,083	84,706
Level 2 [Member] | U.S. equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2 [Member] | International equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2 [Member] | Corporate debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value		5,147
Level 2 [Member] | Total investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	$ 141,083	$ 89,853