Financial Highlights - Schedule of condensed financial information for an accumulation unit of the account (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2022	Sep. 30, 2021	Jun. 30, 2021
Per Accumulation Unit Data:
Rental income (in dollars per share)	$ 17.400	$ 22.672	$ 21.145	$ 18.165
Real estate property level expenses and taxes (in dollars per share)	8.159	10.683	10.067	8.734
Real estate income, net (in dollars per share)	9.241	11.989	11.078	9.431
Other income (in dollars per share)	4.543	5.474	4.980	6.752
Total income (in dollars per share)	13.784	17.463	16.058	16.183
Expense charges (in dollars per share)	3.727	4.035	3.562	3.439
Investment income, net (in dollars per share)	10.057	13.428	12.496	12.744
Net realized and unrealized gain (loss) on investments and debt (in dollars per share)	52.259	64.615	(16.196)	10.262
Net increase (decrease) in Accumulation Unit Value (in dollars per share)	62.316	78.043	(3.700)	23.006
Accumulation Unit Value:
Beginning of period (in dollars per share)	514.765	436.722	440.422	417.416
End of period (in dollars per share)	$ 577.081	$ 514.765	$ 436.722	$ 440.422
Total return	12.11%	17.87%	(0.84%)	5.51%
Ratios to Average net assets:
Expenses	0.88%	0.85%	0.81%	0.78%
Investment income, net	2.37%	2.82%	2.85%	2.90%
Portfolio turnover rate:
Real estate properties	5.10%	7.60%	7.10%	7.80%
Marketable securities	4.10%	0.00%	113.40%	28.70%
Accumulation Units outstanding at end of period (millions) (in shares)	53.5	53.4	52.0	60.8
Net assets end of period (millions)	$ 31,573.4	$ 28,072.0	$ 23,243.9	$ 27,307.9	$ 31,448.8	$ 26,280.4	$ 24,915.3