Earnings Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 unit	Mar. 31, 2011
Numerator - Basic
Income from continuing operations	$ 193,571	$ 73,643
Noncontrolling interests' share in continuing operations	(3,184)	(3,891)
Income from continuing operations applicable to HCP, Inc.	190,387	69,752
Preferred stock dividends	(17,006)	(5,283)
Participating securities' share in continuing operations	(1,117)	(935)
Income from continuing operations applicable to common shares	172,264	63,534
Discontinued operations	2,993	341
Net income applicable to common shares	$ 175,257	$ 63,875
Denominator
Basic weighted-average common shares	410,018,000	372,116,000
Dilutive potential common shares	1,643,000	1,844,000
Diluted weighted-average common shares	411,661,000	373,960,000
Basic earnings per common share
Income from continuing operations (in dollars per share)	$ 0.42	$ 0.17
Discontinued operations (in dollars per share)	$ 0.01
Net income applicable to common shares (in dollars per share)	$ 0.43	$ 0.17
Diluted earnings per common share
Income from continuing operations (in dollars per share)	$ 0.42	$ 0.17
Discontinued operations (in dollars per share)	$ 0.01
Net income applicable to common shares (in dollars per share)	$ 0.43	$ 0.17
DownREIT LLCs, non-managing member units outstanding	4,200,000
Common stock options
Diluted earnings per common share
Shares of anti-dilutive securities excluded from earnings per share calculation	1,100,000	1,200,000
Restricted Stock and Performance Restricted Stock Units
Diluted earnings per common share
Shares of anti-dilutive securities excluded from earnings per share calculation	500,000	12,000
Down REIT
Diluted earnings per common share
Shares of anti-dilutive securities excluded from earnings per share calculation	5,900,000	6,000,000
DownREIT LLCs, non-managing member units outstanding	4,200,000	4,200,000