Acquisitions, Dispositions, Exchanges and Other (Exchanges and Other) (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2014	Sep. 30, 2015	Jan. 31, 2015	Jun. 30, 2014
Berkshire Exchange Transaction [Member]
Exchange And Other [Line Items]
Amount of Cash Exchanged to Berkshire				$ 327.7
Berkshire Exchange Transaction [Member] | Common Class B [Member]
Exchange And Other [Line Items]
Number of shares received in Berkshire Hathaway agreement				1,620,190.00000
Berkshire Exchange Transaction [Member] | Berkshire Hathaway Inc [Member] | Common Class A [Member]
Exchange And Other [Line Items]
Number of Shares Exchanged				2,107
Berkshire Exchange Transaction [Member] | Berkshire Hathaway Inc [Member] | Common Class B [Member]
Exchange And Other [Line Items]
Number of Shares Exchanged				1,278
Celtic Healthcare Allegheny Health Network Joint Venture [Member]
Exchange And Other [Line Items]
Equity Method Investment, Ownership Percentage		40.00%
Celtic Healthcare Allegheny Health Network Joint Venture [Member] | Celtic Healthcare Inc [Member]
Exchange And Other [Line Items]
Equity Method Investment, Ownership Percentage			40.00%
Percentage of revenue	29.00%