Other Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Component of Operating Income [Abstract]
Interest Income (Expense), Net	$ 29,558	$ 7,019	$ 5,866
Pennsylvania Turnpike Settlement	0	9,000	0
Equity in Earnings of Affiliates	(45,061)	(3,518)	(3,706)
Contracts Revenue	30,000	0	0
Royalty Revenue	19,653	16,906	16,853
Right of Way Issuance	7,333	4,536	3,966
Interest Income, Other	2,303	15,889	28,937
Proceeds from Divestiture of Businesses and Interests in Affiliates	1,319	0	0
Service Income	1,188	3,085	3,203
Income (Loss) from Equity Method Investments	49,791	33,133	27,048
Gain on Business Interruption Insurance Recovery	0	5,445	2,300
Other Nonoperating Income (Expense)	20,897	12,952	21,291
Other Income	$ 207,103	$ 111,483	$ 113,170