Guarantor and Non-Guarantor Financial Statements (Balance Sheets) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Assets
Cash held by consolidated investments	$ 1,298,700,000	$ 8,000,000
Cash and cash equivalents	274,400,000	170,200,000
Accounts receivable	28,200,000	16,600,000
Intercompany receivables	0	0
Loans	202,200,000	56,800,000
Real estate and acquired in place lease values, net of accumulated depreciation	1,878,900,000	688,100,000
Unconsolidated investments	619,700,000	786,100,000
Investments in and advances to consolidated subsidiaries		0
Other assets	105,100,000	73,000,000
Total assets	4,407,200,000	1,798,800,000
Liabilities
Accounts payable, accrued expenses and other liabilities	154,700,000	129,100,000
Intercompany payables		0
Senior notes payable	706,100,000	409,000,000
Intercompany loans payable		0
Investment debt	882,200,000	401,800,000
Junior subordinated debentures	40,000,000	40,000,000
Total liabilities	1,783,000,000	979,900,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	952,600,000	768,300,000
Noncontrolling interests	1,671,600,000	50,600,000
Total equity	2,624,200,000	818,900,000
Total liabilities and equity	4,407,200,000	1,798,800,000
Parent [Member]
Assets
Cash held by consolidated investments	0	0
Cash and cash equivalents	0	0
Accounts receivable	0	0
Intercompany receivables	959,700,000	0
Loans	0	0
Real estate and acquired in place lease values, net of accumulated depreciation	0	0
Unconsolidated investments	0	0
Investments in and advances to consolidated subsidiaries		775,100,000
Other assets	0	0
Total assets	959,700,000	775,100,000
Liabilities
Accounts payable, accrued expenses and other liabilities	9,000,000	6,800,000
Intercompany payables		0
Senior notes payable	0	0
Intercompany loans payable		0
Investment debt	0	0
Junior subordinated debentures	0	0
Total liabilities	9,000,000	6,800,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	950,700,000	768,300,000
Noncontrolling interests	0	0
Total equity	950,700,000	768,300,000
Total liabilities and equity	959,700,000	775,100,000
Kennedy-Wilson, Inc. [Member]
Assets
Cash held by consolidated investments	0	0
Cash and cash equivalents	248,300,000	48,200,000
Accounts receivable	0	1,100,000
Intercompany receivables	1,405,100,000	9,000,000
Loans	57,100,000	59,700,000
Real estate and acquired in place lease values, net of accumulated depreciation	0	0
Unconsolidated investments	9,600,000	7,500,000
Investments in and advances to consolidated subsidiaries		1,141,900,000
Other assets	22,700,000	20,900,000
Total assets	1,742,800,000	1,288,300,000
Liabilities
Accounts payable, accrued expenses and other liabilities	37,000,000	64,200,000
Intercompany payables		0
Senior notes payable	706,100,000	409,000,000
Intercompany loans payable		0
Investment debt	0	0
Junior subordinated debentures	40,000,000	40,000,000
Total liabilities	783,100,000	513,200,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	959,700,000	775,100,000
Noncontrolling interests	0	0
Total equity	959,700,000	775,100,000
Total liabilities and equity	1,742,800,000	1,288,300,000
Guarantor Subsidiaries [Member]
Assets
Cash held by consolidated investments	0	0
Cash and cash equivalents	21,600,000	77,200,000
Accounts receivable	18,600,000	7,000,000
Intercompany receivables	727,300,000	0
Loans	182,000,000	53,700,000
Real estate and acquired in place lease values, net of accumulated depreciation	198,600,000	145,300,000
Unconsolidated investments	425,700,000	598,000,000
Investments in and advances to consolidated subsidiaries		326,600,000
Other assets	38,900,000	31,400,000
Total assets	1,612,700,000	1,239,200,000
Liabilities
Accounts payable, accrued expenses and other liabilities	29,700,000	22,900,000
Intercompany payables		0
Senior notes payable	0	0
Intercompany loans payable		0
Investment debt	175,000,000	74,400,000
Junior subordinated debentures	0	0
Total liabilities	204,700,000	97,300,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	1,405,100,000	1,141,900,000
Noncontrolling interests	2,900,000	0
Total equity	1,408,000,000	1,141,900,000
Total liabilities and equity	1,612,700,000	1,239,200,000
Non-Guarantor Subsidiaries [Member]
Assets
Cash held by consolidated investments	1,298,700,000	8,000,000
Cash and cash equivalents	4,500,000	44,800,000
Accounts receivable	9,600,000	8,500,000
Intercompany receivables	(1,900,000)	0
Loans	19,800,000	800,000
Real estate and acquired in place lease values, net of accumulated depreciation	1,680,300,000	542,800,000
Unconsolidated investments	184,400,000	180,600,000
Investments in and advances to consolidated subsidiaries		0
Other assets	43,500,000	20,700,000
Total assets	3,238,900,000	806,200,000
Liabilities
Accounts payable, accrued expenses and other liabilities	79,000,000	35,200,000
Intercompany payables		9,000,000
Senior notes payable	56,700,000	0
Intercompany loans payable		57,400,000
Investment debt	707,200,000	327,400,000
Junior subordinated debentures	0	0
Total liabilities	842,900,000	429,000,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	727,300,000	326,600,000
Noncontrolling interests	1,668,700,000	50,600,000
Total equity	2,396,000,000	377,200,000
Total liabilities and equity	3,238,900,000	806,200,000
Eliminations [Member]
Assets
Cash held by consolidated investments	0	0
Cash and cash equivalents	0	0
Accounts receivable	0	0
Intercompany receivables	(3,090,200,000)	(9,000,000)
Loans	(56,700,000)	(57,400,000)
Real estate and acquired in place lease values, net of accumulated depreciation	0	0
Unconsolidated investments	0	0
Investments in and advances to consolidated subsidiaries		(2,243,600,000)
Other assets	0	0
Total assets	(3,146,900,000)	(2,310,000,000)
Liabilities
Accounts payable, accrued expenses and other liabilities	0	0
Intercompany payables		(9,000,000)
Senior notes payable	(56,700,000)	0
Intercompany loans payable		(57,400,000)
Investment debt	0	0
Junior subordinated debentures	0	0
Total liabilities	(56,700,000)	(66,400,000)
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	(3,090,200,000)	(2,243,600,000)
Noncontrolling interests	0	0
Total equity	(3,090,200,000)	(2,243,600,000)
Total liabilities and equity	$ (3,146,900,000)	$ (2,310,000,000)