Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Numerator
Net income (loss) from continuing operations									$ 422,634	$ 374,171	$ 152,668
Noncontrolling interests' share in earnings									(8,465)	(12,179)	(12,817)
Net income (loss) attributable to HCP, Inc.									414,169	361,992	139,851
Less: Participating securities' share in earnings									(1,156)	(1,198)	(1,317)
Income (loss) from continuing operations applicable to common shares									413,013	360,794	138,534
Discontinued operations					$ (18,246)	$ 108,215	$ 107,378	$ 68,408	0	265,755	(699,086)
Net income (loss) applicable to common shares									$ 413,013	$ 626,549	$ (560,552)
Denominator
Basic weighted average shares outstanding									468,759,000	467,195,000	462,795,000
Dilutive potential common shares - equity awards									176,000	208,000	0
Diluted weighted average common shares									468,935,000	467,403,000	462,795,000
Basic earnings per common share:
Continuing operations (in dollars per share)									$ 0.88	$ 0.77	$ 0.30
Discontinued operations (in dollars per share)									0.00	0.57	(1.51)
Net income (loss) applicable to common shares (in dollars per share)	$ (0.13)	$ (0.02)	$ 0.04	$ 0.98	$ 0.12	$ 0.32	$ 0.65	$ 0.25	0.88	1.34	(1.21)
Diluted earnings per common share
Continuing operations (in dollars per share)									0.88	0.77	0.30
Discontinued operations (in dollars per share)									0.00	0.57	(1.51)
Net income (loss) applicable to common shares (in dollars per share)	$ (0.13)	$ (0.02)	$ 0.04	$ 0.97	$ 0.12	$ 0.32	$ 0.64	$ 0.25	$ 0.88	$ 1.34	$ (1.21)
Common Stock Options
Diluted earnings per common share
Shares of anti-dilutive securities excluded from earnings per share calculation									1,000,000	1,000,000	1,000,000