Commitments and Contingencies (Details 2) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2012	Sep. 01, 2011 item
Commitments and contingencies
Third party debt collateralized by facilities, debt amount (maturing in May 1, 2025)			$ 120
Third party debt collateralized by facilities, asset carrying amount (maturing in May 1, 2025)		372	372
Brookdale Senior Living, Inc.
Commitments and contingencies
Number of senior housing communities				37
Number of senior housing communities assumed in existing triple-net lease				9
Number of senior housing communities in new triple-net lease				4
Number of senior housing communities assumed formerly managed by Horizon Bay				3
Number of senior housing communities developed by HCP				1
Interest in real estate and operations of senior living communities (as a percent)				10.00%
Purchase of equity marketable securities	22.4
Concentration risk, revenue		35.6	70.7
Concentration risk, operating expenses		$ 22.7	$ 43.4