Guarantor and Non-Guarantor Financial Statements (Balance Sheets) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 349,500,000	$ 170,200,000
Cash held by consolidated investments (including $42.6 and $0 of restricted cash)	292,800,000	8,000,000
Accounts receivable	36,800,000	16,600,000
Intercompany receivables	0	0
Loans	402,300,000	56,800,000
Real estate and acquired in place lease values, net of accumulated depreciation	3,553,400,000	688,100,000
Unconsolidated investments	532,200,000	786,100,000
Investments in and advances to consolidated subsidiaries		0
Other assets	187,700,000	73,000,000
Total assets	5,354,700,000	1,798,800,000
Liabilities
Accounts payable, accrued expenses and other liabilities	285,700,000	129,100,000
Intercompany payables		0
Senior notes payable	706,000,000	409,000,000
Intercompany loans payable		0
Investment debt	1,528,700,000	401,800,000
Junior subordinated debentures	40,000,000	40,000,000
Total liabilities	2,560,400,000	979,900,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	976,100,000	768,300,000
Noncontrolling interests	1,818,200,000	50,600,000
Total equity	2,794,300,000	818,900,000
Total liabilities and equity	5,354,700,000	1,798,800,000
Parent [Member]
Assets
Cash and cash equivalents	0	0
Cash held by consolidated investments (including $42.6 and $0 of restricted cash)	0	0
Accounts receivable	0	0
Intercompany receivables	988,600,000	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	988,600,000	775,100,000
Liabilities
Accounts payable, accrued expenses and other liabilities	11,100,000	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	11,100,000	6,800,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	977,500,000	768,300,000
Noncontrolling interests	0	0
Total equity	977,500,000	768,300,000
Total liabilities and equity	988,600,000	775,100,000
Kennedy-Wilson, Inc. [Member]
Assets
Cash and cash equivalents	328,400,000	48,200,000
Cash held by consolidated investments (including $42.6 and $0 of restricted cash)	0	0
Accounts receivable	0	1,100,000
Intercompany receivables	1,401,300,000	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	9,300,000	7,500,000
Investments in and advances to consolidated subsidiaries		1,141,900,000
Other assets	23,500,000	20,900,000
Total assets	1,819,600,000	1,288,300,000
Liabilities
Accounts payable, accrued expenses and other liabilities	85,000,000	64,200,000
Intercompany payables		0
Senior notes payable	706,000,000	409,000,000
Intercompany loans payable		0
Investment debt	0	0
Junior subordinated debentures	40,000,000	40,000,000
Total liabilities	831,000,000	513,200,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	988,600,000	775,100,000
Noncontrolling interests	0	0
Total equity	988,600,000	775,100,000
Total liabilities and equity	1,819,600,000	1,288,300,000
Guarantor Subsidiaries [Member]
Assets
Cash and cash equivalents	20,400,000	77,200,000
Cash held by consolidated investments (including $42.6 and $0 of restricted cash)	0	0
Accounts receivable	16,000,000	7,000,000
Intercompany receivables	859,800,000	0
Loans	180,900,000	53,700,000
Real estate and acquired in place lease values, net of accumulated depreciation	194,200,000	145,300,000
Unconsolidated investments	290,700,000	598,000,000
Investments in and advances to consolidated subsidiaries		326,600,000
Other assets	41,900,000	31,400,000
Total assets	1,603,900,000	1,239,200,000
Liabilities
Accounts payable, accrued expenses and other liabilities	25,600,000	22,900,000
Intercompany payables		0
Senior notes payable	0	0
Intercompany loans payable		0
Investment debt	176,700,000	74,400,000
Junior subordinated debentures	0	0
Total liabilities	202,300,000	97,300,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	1,401,300,000	1,141,900,000
Noncontrolling interests	300,000	0
Total equity	1,401,600,000	1,141,900,000
Total liabilities and equity	1,603,900,000	1,239,200,000
Non-Guarantor Subsidiaries [Member]
Assets
Cash and cash equivalents	700,000	44,800,000
Cash held by consolidated investments (including $42.6 and $0 of restricted cash)	292,800,000	8,000,000
Accounts receivable	20,800,000	8,500,000
Intercompany receivables	1,400,000	0
Loans	221,000,000	800,000
Real estate and acquired in place lease values, net of accumulated depreciation	3,359,200,000	542,800,000
Unconsolidated investments	232,200,000	180,600,000
Investments in and advances to consolidated subsidiaries		0
Other assets	122,300,000	20,700,000
Total assets	4,250,400,000	806,200,000
Liabilities
Accounts payable, accrued expenses and other liabilities	164,000,000	35,200,000
Intercompany payables		9,000,000
Senior notes payable	0	0
Intercompany loans payable		57,400,000
Investment debt	1,408,700,000	327,400,000
Junior subordinated debentures	0	0
Total liabilities	1,572,700,000	429,000,000
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	859,800,000	326,600,000
Noncontrolling interests	1,817,900,000	50,600,000
Total equity	2,677,700,000	377,200,000
Total liabilities and equity	4,250,400,000	806,200,000
Eliminations [Member]
Assets
Cash and cash equivalents	0	0
Cash held by consolidated investments (including $42.6 and $0 of restricted cash)	0	0
Accounts receivable	0	0
Intercompany receivables	(3,251,100,000)	(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	(3,307,800,000)	(2,310,000,000)
Liabilities
Accounts payable, accrued expenses and other liabilities	0	0
Intercompany payables		(9,000,000)
Senior notes payable	0	0
Intercompany loans payable		(57,400,000)
Investment debt	(56,700,000)	0
Junior subordinated debentures	0	0
Total liabilities	(56,700,000)	(66,400,000)
Equity
Kennedy-Wilson Holdings, Inc. shareholders' equity	(3,251,100,000)	(2,243,600,000)
Noncontrolling interests	0	0
Total equity	(3,251,100,000)	(2,243,600,000)
Total liabilities and equity	$ (3,307,800,000)	$ (2,310,000,000)