Earnings Per Common Share (Details) $ / shares in Units, $ in Thousands, item in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015 $ / shares	Sep. 30, 2015 $ / shares	Jun. 30, 2015 $ / shares	Mar. 31, 2015 $ / shares	Dec. 31, 2014 $ / shares	Sep. 30, 2014 $ / shares	Jun. 30, 2014 $ / shares	Mar. 31, 2014 USD ($) $ / shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) item $ / shares shares	Dec. 31, 2013 USD ($) item $ / shares shares	Dec. 31, 2012 item shares
Numerator
(Loss) income from continuing operations									$ (546,418)	$ 906,845	$ 910,633
Noncontrolling interests' share in continuing operations									(12,817)	(13,181)	(14,110)
(Loss) income from continuing operations applicable to HCP, Inc.									(559,235)	893,664	896,523
Participating securities' share in earnings									(1,317)	(2,437)	(1,734)
(Loss) income from continuing operations applicable to common shares									(560,552)	891,227	894,789
Discontinued operations								$ 29,746		29,746	74,373
Noncontrolling interests' share in discontinued operations										(1,177)	(59)
Net (loss) income applicable to common shares									$ (560,552)	$ 919,796	$ 969,103
Denominator
Basic weighted average common shares | shares									462,795,000	458,425,000	455,002,000
Dilutive potential common shares | shares										371,000	700,000
Diluted weighted average common shares | shares									462,795,000	458,796,000	455,702,000
Basic earnings per common share
(Loss) income from continuing operations | $ / shares									$ (1.21)	$ 1.94	$ 1.97
Discontinued operations (in dollars per share) | $ / shares										0.07	0.16
Net (loss) income applicable to common shares (in dollars per share) | $ / shares	$ (1.290)	$ 0.250	$ 0.360	$ (0.520)	$ 0.43	$ 0.54	$ 0.48	$ 0.56	(1.21)	2.01	2.13
Diluted earnings per common share
(Loss) income from continuing operations | $ / shares									(1.21)	1.94	1.97
Discontinued operations (in dollars per share) | $ / shares										0.06	0.16
Net (loss) income applicable to common shares (in dollars per share) | $ / shares	$ (1.290)	$ 0.250	$ 0.360	$ (0.520)	$ 0.43	$ 0.54	$ 0.48	$ 0.56	$ (1.21)	$ 2.00	$ 2.13
Common Stock Options
Diluted earnings per common share
Shares of anti-dilutive securities excluded from earnings per share calculation | shares										1,400,000	800,000
Down REIT
Diluted earnings per common share
Shares of anti-dilutive securities excluded from earnings per share calculation | shares										6,000,000	6,000,000	6,000,000
DownREIT LLCs, non-managing member units outstanding | item										4	4	4