Consolidated Statements of Equity - USD ($) $ in Millions	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]	Foreign Exchange Contract [Member]	Foreign Exchange Contract [Member] Accumulated Other Comprehensive Loss [Member]	Foreign Exchange Contract [Member] Noncontrolling Interests [Member]	Interest Rate Swap [Member]	Interest Rate Swap [Member] Accumulated Other Comprehensive Loss [Member]
Balance, beginning of period, preferred shares (in shares) at Dec. 31, 2016		0
Balance at beginning of period at Dec. 31, 2016	$ 2,343.1	$ 0.0	$ 0.0	$ 1,231.4	$ (112.2)	$ (71.2)	$ 1,295.1
Balance, beginning of period, common shares (in shares) at Dec. 31, 2016			115,740,906
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issuance (in shares)			37,226,695
Stock issuance	(823.2)			680.7		(358.4)	(1,145.5)
Shares forfeited (in shares)			(57,000)
Restricted stock grants (RSG) (in shares)			1,756,750
Shares retired due to RSG Vesting (in shares)			(1,460,251)
Shares retired due to RSG Vesting	(37.9)			(37.9)
Shares retired due to common stock repurchase program (in shares)			(1,645,816)
Shares retired due to common stock repurchase program	(29.9)			(29.1)	(0.8)
Stock based compensation	38.2			38.2
Other comprehensive income (loss):
Unrealized foreign currency translation (losses) gains, net of tax	158.4					52.0	106.4
Unrealized foreign currency derivative contract gain, net of tax								$ (69.4)	$ (49.7)	$ (19.7)
Unrealized losses on marketable securities	0.2					0.2
Common stock dividends	(87.4)				(87.4)
Net income	138.0				100.5		37.5
Acquisition of Kennedy Wilson Europe (KWE) shares from noncontrolling interest holders	(3.3)						(3.3)
Contributions from noncontrolling interests, excluding KWE	47.4						47.4
Distributions to noncontrolling interests	(106.0)						(106.0)
Balance, end of period, preferred shares (in shares) at Dec. 31, 2017		0
Balance at end of period at Dec. 31, 2017	1,577.5	$ 0.0	$ 0.0	1,883.3	(90.6)	(427.1)	211.9
Balance, end of period, common shares (in shares) at Dec. 31, 2017			151,561,284
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares forfeited (in shares)			(30,100)
Restricted stock grants (RSG) (in shares)			1,524,383
Shares retired due to RSG Vesting (in shares)			(486,032)
Shares retired due to RSG Vesting	(8.8)			(8.8)
Shares retired due to common stock repurchase program (in shares)			(9,364,141)
Shares retired due to common stock repurchase program			$ (169.1)	(167.0)	(2.1)
Stock based compensation	37.1			37.1
Other comprehensive income (loss):
Unrealized foreign currency translation (losses) gains, net of tax	(44.2)					(47.5)	3.3
Unrealized foreign currency derivative contract gain, net of tax								33.2	33.2
Unrealized losses on marketable securities	(0.1)					(0.1)	0.0
Common stock dividends	(113.7)				(113.7)
Net income	212.1				150.0		62.1
Contributions from noncontrolling interests, excluding KWE	23.2						23.2
Distributions to noncontrolling interests	(116.0)						(116.0)
Balance, end of period, preferred shares (in shares) at Dec. 31, 2018		0
Balance at end of period at Dec. 31, 2018	$ 1,431.2	$ 0.0	$ 0.0	1,744.6	(56.4)	(441.5)	184.5
Balance, end of period, common shares (in shares) at Dec. 31, 2018	143,205,394		143,205,394
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issuance (in shares)		300,000
Stock issuance	$ 295.2	$ 295.2
Restricted stock grants (RSG) (in shares)			64,458
Shares retired due to RSG Vesting (in shares)			(764,909)
Shares retired due to RSG Vesting	(16.4)			(16.4)
Shares retired due to common stock repurchase program (in shares)			(221,834)
Shares retired due to common stock repurchase program			$ (4.3)	(3.9)	(0.4)
Stock based compensation	30.2			30.2
Other comprehensive income (loss):
Unrealized foreign currency translation (losses) gains, net of tax	6.3					(4.3)	10.6
Unrealized currency derivative contract gain (loss)	(0.7)							$ 29.3	$ 29.3		$ (0.7)	$ (0.7)
Common stock dividends	(121.1)				(121.1)
Preferred stock dividends	(2.6)
Net income	321.1				226.7		94.4
Contributions from noncontrolling interests, excluding KWE	15.0						15.0
Distributions to noncontrolling interests	$ (264.0)						(264.0)
Balance, end of period, preferred shares (in shares) at Dec. 31, 2019	300,000	300,000
Balance at end of period at Dec. 31, 2019	$ 1,719.2	$ 295.2	$ 0.0	$ 1,754.5	$ 46.2	$ (417.2)	$ 40.5
Balance, end of period, common shares (in shares) at Dec. 31, 2019	142,283,109		142,283,109