Segment Reporting - Summary of Financial Results by Segment (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Total revenues	$ 635,371,000	$ 438,033,000	$ 1,903,000,000	$ 1,089,432,000
Expenses:
Total expenses	253,645,000	211,542,000	752,897,000	515,081,000
Income from unconsolidated entities	25,073,000		63,678,000
Income (loss) from investments in real estate debt	206,046,000	52,568,000	(317,212,000)	166,035,000
Segment net operating income (loss)	612,845,000	279,059,000	896,569,000	740,386,000
Depreciation and amortization	(332,599,000)	(204,653,000)	(1,008,756,000)	(505,986,000)
General and administrative	(5,430,000)	(4,548,000)	(19,025,000)	(12,607,000)
Management fee	(57,619,000)	(29,858,000)	(160,544,000)	(69,522,000)
Performance participation allocation	0	(56,322,000)	0	(106,383,000)
Impairment of investments in real estate	(6,217,000)		(12,343,000)	0
Net Gain	100,070,000	6,481,000	100,441,000	36,167,000
Interest income	122,000	1,763,000	2,102,000	2,260,000
Interest expense	(174,193,000)	(116,037,000)	(539,276,000)	(310,903,000)
Loss on extinguishment of debt	(5,258,000)		(6,495,000)	0
Other income (expense)	(9,252,000)	(2,379,000)	(29,022,000)	(2,786,000)
Net income (loss)	122,469,000	(126,494,000)	(776,349,000)	(229,374,000)
Net loss attributable to non-controlling interests in third party joint ventures	593,000	1,305,000	1,796,000	4,311,000
Net income attributable to non-controlling interests in BREIT OP	(1,790,000)	2,018,000	10,177,000	4,342,000
Net income (loss) attributable to BREIT stockholders	121,272,000	(123,171,000)	(764,376,000)	(220,721,000)
Multifamily [Member]
Revenues:
Total revenues	257,717,000	195,068,000	752,721,000	498,858,000
Expenses:
Total expenses	122,266,000	90,149,000	342,062,000	225,745,000
Segment net operating income (loss)	135,451,000	104,919,000	410,659,000	273,113,000
Depreciation and amortization	(133,696,000)	(128,043,000)	(406,617,000)	(303,208,000)
Industrial [Member]
Revenues:
Total revenues	214,781,000	102,114,000	627,759,000	269,095,000
Expenses:
Total expenses	62,002,000	28,813,000	183,220,000	79,870,000
Segment net operating income (loss)	152,779,000	73,301,000	444,539,000	189,225,000
Depreciation and amortization	(135,978,000)	(52,720,000)	(412,900,000)	(145,145,000)
Net Lease [Member]
Revenues:
Total revenues	82,795,000		248,384,000
Expenses:
Total expenses	156,000		270,000
Income from unconsolidated entities	25,073,000		63,678,000
Segment net operating income (loss)	107,712,000		311,792,000
Depreciation and amortization	(28,667,000)		(85,862,000)
Hotel [Member]
Revenues:
Total revenues	57,776,000	134,178,000	209,866,000	308,597,000
Expenses:
Total expenses	60,339,000	89,951,000	204,168,000	204,468,000
Segment net operating income (loss)	(2,563,000)	44,227,000	5,698,000	104,129,000
Depreciation and amortization	(22,296,000)	(19,003,000)	(67,842,000)	(49,686,000)
Retail [Member]
Revenues:
Total revenues	13,849,000	3,814,000	41,277,000	10,023,000
Expenses:
Total expenses	5,163,000	1,387,000	12,914,000	3,756,000
Segment net operating income (loss)	8,686,000	2,427,000	28,363,000	6,267,000
Depreciation and amortization	(7,978,000)	(1,938,000)	(24,787,000)	(4,998,000)
Other Properties [Member]
Revenues:
Total revenues	5,227,000	2,859,000	13,599,000	2,859,000
Expenses:
Total expenses	2,618,000	1,242,000	7,061,000	1,242,000
Segment net operating income (loss)	2,609,000	1,617,000	6,538,000	1,617,000
Depreciation and amortization	(2,396,000)	(2,949,000)	(6,077,000)	(2,949,000)
Real Estate Debt [Member]
Expenses:
Income (loss) from investments in real estate debt	206,046,000	52,568,000	(317,212,000)	166,035,000
Segment net operating income (loss)	206,046,000	52,568,000	(317,212,000)	166,035,000
Office [Member]
Revenues:
Total revenues	3,226,000		9,394,000
Expenses:
Total expenses	1,101,000		3,202,000
Segment net operating income (loss)	2,125,000		6,192,000
Depreciation and amortization	(1,588,000)		(4,671,000)
Rental Property [Member]
Revenues:
Total revenues	562,053,000	290,453,000	1,647,865,000	750,322,000
Expenses:
Total expenses	193,306,000	121,591,000	548,729,000	310,613,000
Rental Property [Member] | Multifamily [Member]
Revenues:
Total revenues	244,691,000	183,429,000	713,603,000	470,570,000
Expenses:
Total expenses	122,266,000	90,149,000	342,062,000	225,745,000
Rental Property [Member] | Industrial [Member]
Revenues:
Total revenues	213,302,000	100,759,000	624,282,000	267,428,000
Expenses:
Total expenses	62,002,000	28,813,000	183,220,000	79,870,000
Rental Property [Member] | Net Lease [Member]
Revenues:
Total revenues	82,795,000		248,384,000
Expenses:
Total expenses	156,000		270,000
Rental Property [Member] | Retail [Member]
Revenues:
Total revenues	13,594,000	3,723,000	40,516,000	9,782,000
Expenses:
Total expenses	5,163,000	1,387,000	12,914,000	3,756,000
Rental Property [Member] | Other Properties [Member]
Revenues:
Total revenues	4,541,000	2,542,000	12,002,000	2,542,000
Expenses:
Total expenses	2,618,000	1,242,000	7,061,000	1,242,000
Rental Property [Member] | Office [Member]
Revenues:
Total revenues	3,130,000		9,078,000
Expenses:
Total expenses	1,101,000		3,202,000
Hotel [Member]
Revenues:
Total revenues	56,038,000	132,036,000	205,291,000	301,653,000
Expenses:
Total expenses	60,339,000	89,951,000	204,168,000	204,468,000
Hotel [Member] | Hotel [Member]
Revenues:
Total revenues	56,038,000	132,036,000	205,291,000	301,653,000
Expenses:
Total expenses	60,339,000	89,951,000	204,168,000	204,468,000
Other Revenue [Member]
Revenues:
Total revenues	17,280,000	15,544,000	49,844,000	37,457,000
Other Revenue [Member] | Multifamily [Member]
Revenues:
Total revenues	13,026,000	11,639,000	39,118,000	28,288,000
Other Revenue [Member] | Industrial [Member]
Revenues:
Total revenues	1,479,000	1,355,000	3,477,000	1,667,000
Other Revenue [Member] | Hotel [Member]
Revenues:
Total revenues	1,738,000	2,142,000	4,575,000	6,944,000
Other Revenue [Member] | Retail [Member]
Revenues:
Total revenues	255,000	91,000	761,000	241,000
Other Revenue [Member] | Other Properties [Member]
Revenues:
Total revenues	686,000	$ 317,000	1,597,000	$ 317,000
Other Revenue [Member] | Office [Member]
Revenues:
Total revenues	$ 96,000		$ 316,000