Acquisitions and Divestitures (Divestitures Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	0 Months Ended
	Mar. 31, 2015 item	Mar. 01, 2015	Dec. 31, 2014	Feb. 01, 2015	Jan. 01, 2015 item
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Hospitals Sold	4
Proceeds from Divestiture of Businesses, Net of Cash Divested	$ 62
Riverview Regional Medical Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Date	Mar. 01, 2015
Number of licensed beds		281
Proceeds from Divestiture of Businesses, Net of Cash Divested		25
Carolina Pines Regional Medical Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Date	Jan. 01, 2015
Number of licensed beds					116
Proceeds from Divestiture of Businesses, Net of Cash Divested			74
Williamson Memorial Hospital [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of licensed beds	76
Harris Hospital [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Date	Feb. 01, 2015
Number of licensed beds				133
Proceeds from Divestiture of Businesses, Net of Cash Divested				5
Dallas Regional Medical Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Date	Mar. 01, 2015
Number of licensed beds		202
Proceeds from Divestiture of Businesses, Net of Cash Divested		$ 25