Earnings Per Common Share - Schedule of Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator
Net income (loss)	$ 102,926	$ (5,720)	$ 239,091	$ 480,558
Noncontrolling interests' share in earnings	(3,555)	(1,937)	(9,546)	(7,687)
Net income (loss) attributable to HCP, Inc.	99,371	(7,657)	229,545	472,871
Less: Participating securities' share in earnings	(425)	(131)	(1,278)	(560)
Net income (loss) applicable to common shares	$ 98,946	$ (7,788)	$ 228,267	$ 472,311
Denominator
Basic weighted average common shares	469,867	468,975	469,732	468,642
Dilutive potential common shares	251	0	144	186
Diluted weighted average common shares	470,118	468,975	469,876	468,828
Earnings per common share:
Earnings per common share, basic (in dollars per share)	$ 0.21	$ (0.02)	$ 0.49	$ 1.01
Earnings per common share, diluted (in dollars per share)	$ 0.21	$ (0.02)	$ 0.49	$ 1.01
Down REIT
Earnings per common share:
Shares of anti-dilutive securities excluded from earnings per share calculation	7,000	7,000	7,000	7,000
Common Stock Options
Earnings per common share:
Shares of anti-dilutive securities excluded from earnings per share calculation	1,000	1,000	1,000	1,000