Borrowing Arrangements (Senior Notes) (Details) CAD in Millions	1 Months Ended									12 Months Ended
	Sep. 30, 2016 USD ($)	Jul. 31, 2016 USD ($)	Jun. 30, 2016 USD ($)	May 31, 2016 USD ($)	Sep. 30, 2015 USD ($)	Jul. 31, 2015 USD ($)	May 31, 2015 USD ($)	Jan. 31, 2015 CAD	Jan. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 CAD	Dec. 31, 2016 USD ($)	Sep. 30, 2016 CAD	May 31, 2016 CAD	Feb. 29, 2016 USD ($)
Debt Instrument [Line Items]
Principal amount outstanding											$ 11,271,020,000			$ 11,190,914,000
Debt instrument, face amount																	$ 200,000,000
Interest rate																	1.132%
Gain (loss) on extinguishment of debt										$ (2,779,000)	(14,411,000)	$ (5,564,000)
Senior Notes | 3.500% Senior Notes due 2025
Debt Instrument [Line Items]
Debt instrument, face amount									$ 600,000,000.0
Interest rate									3.50%
Public offering price as percent of par									99.663%
Proceeds from issuance of debt									$ 598,000,000
Senior Notes | 4.375% Senior Notes due 2045
Debt Instrument [Line Items]
Debt instrument, face amount									$ 300,000,000.0
Interest rate									4.375%
Public offering price as percent of par									99.50%
Proceeds from issuance of debt									$ 298,500,000
Senior Notes | 6% Senior Notes due 2015
Debt Instrument [Line Items]
Interest rate																6.00%
Repayments of debt							$ 234,400,000
Senior Notes | 4.125% Senior Notes due 2026
Debt Instrument [Line Items]
Debt instrument, face amount						$ 500,000,000.0
Interest rate						4.125%
Public offering price as percent of par						99.218%
Proceeds from issuance of debt						$ 496,100,000
Senior Notes | 3.125% Senior Notes due 2015
Debt Instrument [Line Items]
Interest rate					3.125%
Debt instrument, redemption price rate					100.70%
Gain (loss) on extinguishment of debt					$ (2,900,000)
Repayments of debt					$ 400,000,000
Senior Notes | 6.90% Senior Notes due 2037
Debt Instrument [Line Items]
Interest rate													6.90%	6.90%
Senior Notes | 6.59% Senior Notes due 2038
Debt Instrument [Line Items]
Interest rate													6.59%	6.59%
Senior Notes, Due 2023
Debt Instrument [Line Items]
Principal amount outstanding | CAD																CAD 400.0
Interest rate																3.125%
Public offering price as percent of par			100.335%													99.343%
Proceeds from public offering sale of debt				$ 397,400,000
Gain (loss) on extinguishment of debt			$ 2,100,000
1.55% Senior Notes due 2016
Debt Instrument [Line Items]
Principal amount outstanding											550,000,000			$ 0
Interest rate			1.55%										1.55%	1.55%
Gain (loss) on extinguishment of debt		$ (300,000)
Repayments of debt		$ 94,500,000.0	$ 455,500,000
Senior Notes Due 2026 3.25%
Debt Instrument [Line Items]
Principal amount outstanding | CAD															CAD 450.0
Interest rate															3.25%
Public offering price as percent of par															99.811%
Proceeds from public offering sale of debt	$ 449,100,000
Nhp | Senior Notes
Debt Instrument [Line Items]
Principal amount outstanding														$ 75,400,000
Ventas Realty
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt										$ (2,770,000)	$ (4,523,000)	$ (3,000)
Ventas Realty | Senior Notes
Debt Instrument [Line Items]
Principal amount outstanding														7,100,000,000
Ventas Capital Corporation | Senior Notes
Debt Instrument [Line Items]
Principal amount outstanding														$ 3,900,000,000
Ventas Canada Finance Limited | Senior Notes
Debt Instrument [Line Items]
Principal amount outstanding | CAD													CAD 900.0
Ventas Canada Finance Limited | Senior Notes | Ventas Canada Finance Limited Series C Senior Notes due 2022
Debt Instrument [Line Items]
Debt instrument, face amount									$ 250,000,000
Interest rate									3.30%
Public offering price as percent of par									99.992%
Proceeds from public offering sale of debt | CAD								CAD 250.0