Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings per common share:
Maximum shares issuable under forward equity sales agreement (in shares)	15,250,000.00
Numerator
Net income (loss) from continuing operations										$ 1,073,474	$ 422,634	$ 374,171
Noncontrolling interests' share in earnings										(12,381)	(8,465)	(12,179)
Net income (loss) attributable to HCP, Inc.										1,061,093	414,169	361,992
Less: Participating securities' share in earnings										(2,669)	(1,156)	(1,198)
Income (loss) from continuing operations applicable to common shares										1,058,424	413,013	360,794
Discontinued operations										0	0	265,755
Net income (loss) applicable to common shares										1,058,424	413,013	626,549
Add: distributions on dilutive convertible units and other										6,919	0	0
Dilutive net income (loss) available to common shares										$ 1,065,343	$ 413,013	$ 626,549
Denominator
Basic weighted average shares outstanding (in shares)										470,551,000	468,759,000	467,195,000
Dilutive potential common shares - equity awards (in shares)										168,000	176,000	208,000
Dilutive potential common shares - DownREIT conversions (in shares)										4,668,000	0	0
Diluted weighted average common shares (in shares)										475,387,000	468,935,000	467,403,000
Basic earnings per common share:
Continuing operations (in dollars per share)										$ 2.25	$ 0.88	$ 0.77
Discontinued operations (in dollars per share)										0.00	0.00	0.57
Net income (loss) applicable to common shares (in dollars per share)		$ 1.75	$ 0.21	$ 0.19	$ 0.08	$ (0.13)	$ (0.02)	$ 0.04	$ 0.98	2.25	0.88	1.34
Diluted earnings per common share
Continuing operations (in dollars per share)										2.24	0.88	0.77
Discontinued operations (in dollars per share)										0.00	0.00	0.57
Net income (loss) applicable to common shares (in dollars per share)		$ 1.73	$ 0.21	$ 0.19	$ 0.08	$ (0.13)	$ (0.02)	$ 0.04	$ 0.97	$ 2.24	$ 0.88	$ 1.34
Common Stock Options
Diluted earnings per common share
Antidilutive securities excluded from computation of earnings per share (in shares)										1,000,000	1,000,000	1,000,000
Convertible Units
Diluted earnings per common share
Antidilutive securities excluded from computation of earnings per share (in shares)										2,000,000	7,000,000	7,000,000