Debt (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2021 USD ($) financial_institution line_of_credit	Dec. 31, 2020 USD ($)	Sep. 01, 2020 USD ($)
Line of Credit
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 800,000,000.0
Maximum incremental increase	200,000,000.0
Amount outstanding	0	$ 0
Line of Credit | Subsidiaries
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 165,000,000.0
Number of uncommitted lines of credit | line_of_credit	3
Number of financial institutions offering lines of credit | financial_institution	3
Number of financial institutions with stated limits | line_of_credit	2
Commercial Paper
Short-term Debt [Line Items]
Weighted average interest rates on average daily borrowings	0.20%	0.40%
Short-term debt	$ 0	$ 0
Short-term debt, average outstanding amount	110,800,000	$ 83,200,000
Uncommited Lines of Credit
Short-term Debt [Line Items]
Weighted average interest rates		1.60%
Short-term debt	0	$ 0
Short-term debt, average outstanding amount		900,000
EQH
Short-term Debt [Line Items]
Amount outstanding	$ 590,000,000.0	675,000,000.0
Weighted average interest rates	0.20%
Average daily borrowings	$ 551,200,000	$ 470,800,000
Weighted average interest rates on average daily borrowings	0.20%	0.50%
Revolving Credit Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 200,000,000.0
Revolving Credit Facility | Line of Credit
Short-term Debt [Line Items]
Amount outstanding	$ 0	$ 0
Weighted average interest rates	1.10%	1.60%
Average daily borrowings	$ 22,000,000.0	$ 16,500,000
Revolving Credit Facility | EQH
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	900,000,000.0
Revolving Credit Facility | EQH Uncommitted Facility
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity			$ 300,000,000.0
Amount outstanding	$ 0	$ 0