Commitments and Contingencies (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended		12 Months Ended																																			12 Months Ended
	Dec. 31, 2010 Sunrise Senior Living	Oct. 31, 2010 Sunrise Senior Living item	Dec. 31, 2012 Senior housing Brookdale Senior Living item	Dec. 31, 2011 Senior housing Brookdale Senior Living	Dec. 31, 2012 Gross Assets California	Dec. 31, 2011 Gross Assets California	Dec. 31, 2012 Gross Assets Operators HCR ManorCare	Dec. 31, 2011 Gross Assets Operators HCR ManorCare	Dec. 31, 2012 Gross Assets Operators Brookdale Senior Living	Dec. 31, 2011 Gross Assets Operators Brookdale Senior Living	Dec. 31, 2012 Gross Assets Operators Emeritus Corporation	Dec. 31, 2011 Gross Assets Operators Emeritus Corporation	Dec. 31, 2012 Gross Assets Operators Sunrise Senior Living	Dec. 31, 2011 Gross Assets Operators Sunrise Senior Living	Dec. 31, 2012 Gross Assets Operators Senior housing HCR ManorCare	Dec. 31, 2011 Gross Assets Operators Senior housing HCR ManorCare	Dec. 31, 2012 Gross Assets Operators Senior housing Brookdale Senior Living	Dec. 31, 2011 Gross Assets Operators Senior housing Brookdale Senior Living	Dec. 31, 2012 Gross Assets Operators Senior housing Emeritus Corporation	Dec. 31, 2011 Gross Assets Operators Senior housing Emeritus Corporation	Dec. 31, 2012 Gross Assets Operators Senior housing Sunrise Senior Living	Dec. 31, 2011 Gross Assets Operators Senior housing Sunrise Senior Living	Dec. 31, 2012 Gross Assets Operators Post-acute/skilled nursing HCR ManorCare	Dec. 31, 2011 Gross Assets Operators Post-acute/skilled nursing HCR ManorCare	Dec. 31, 2012 Revenue California	Dec. 31, 2012 Revenue Texas	Dec. 31, 2012 Revenue Florida	Dec. 31, 2012 Revenue Operators HCR ManorCare	Dec. 31, 2011 Revenue Operators HCR ManorCare	Dec. 31, 2010 Revenue Operators HCR ManorCare	Dec. 31, 2012 Revenue Operators Brookdale Senior Living	Dec. 31, 2011 Revenue Operators Brookdale Senior Living	Dec. 31, 2010 Revenue Operators Brookdale Senior Living	Dec. 31, 2012 Revenue Operators Emeritus Corporation	Dec. 31, 2011 Revenue Operators Emeritus Corporation	Dec. 31, 2010 Revenue Operators Emeritus Corporation	Nov. 01, 2010 Revenue Operators Emeritus Corporation item	Dec. 31, 2012 Revenue Operators Sunrise Senior Living	Dec. 31, 2011 Revenue Operators Sunrise Senior Living	Dec. 31, 2010 Revenue Operators Sunrise Senior Living	Dec. 31, 2012 Revenue Operators Senior housing HCR ManorCare	Dec. 31, 2011 Revenue Operators Senior housing HCR ManorCare	Dec. 31, 2012 Revenue Operators Senior housing Brookdale Senior Living	Dec. 31, 2011 Revenue Operators Senior housing Brookdale Senior Living	Dec. 31, 2010 Revenue Operators Senior housing Brookdale Senior Living	Dec. 31, 2012 Revenue Operators Senior housing Emeritus Corporation	Dec. 31, 2011 Revenue Operators Senior housing Emeritus Corporation	Dec. 31, 2010 Revenue Operators Senior housing Emeritus Corporation	Dec. 31, 2012 Revenue Operators Senior housing Sunrise Senior Living	Dec. 31, 2011 Revenue Operators Senior housing Sunrise Senior Living	Dec. 31, 2010 Revenue Operators Senior housing Sunrise Senior Living	Dec. 31, 2012 Revenue Operators Post-acute/skilled nursing HCR ManorCare	Dec. 31, 2011 Revenue Operators Post-acute/skilled nursing HCR ManorCare	Dec. 31, 2010 Revenue Operators Post-acute/skilled nursing HCR ManorCare
Concentration of Credit Risk
Concentration risk (as a percent)					23.00%	20.00%	31.00%	35.00%	4.00%	5.00%	13.00%	6.00%	7.00%	7.00%	11.00%	14.00%	11.00%	14.00%	35.00%	19.00%	17.00%	22.00%	89.00%	94.00%	22.00%	12.00%	10.00%	30.00%	27.00%	9.00%	5.00%	7.00%	5.00%	8.00%	7.00%	6.00%		5.00%	6.00%	9.00%	11.00%	10.00%	14.00%	22.00%	11.00%	23.00%	24.00%	14.00%	15.00%	19.00%	21.00%	90.00%	84.00%	30.00%
Concentration risk, assets			$ 692	$ 683
Concentration risk, revenue	$ 33		$ 143	$ 47
Number of senior living communities operated in a RIDEA structure		27	21																																		27
Number of VIE tenants		4
Percentage of operator assets to segment assets after inclusion of assets under RIDEA structure																	20.00%	26.00%
Percentage of operator assets to total entity assets after inclusion of assets under RIDEA structure									8.00%	9.00%
Percentage of operator revenue to segment revenue after inclusion of revenue under RIDEA structure	28.00%																																	12.00%									36.00%	31.00%		36.00%
Percentage of operator revenue to total entity revenue after inclusion of revenue under RIDEA structure	12.00%																														12.00%	10.00%