Related Party Transactions (Narrative) (Details) - USD ($)	3 Months Ended							12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Other long-term investments	$ 335,811,000			$ 551,931,000				$ 335,811,000	$ 551,931,000
Net investment income								422,809,000	338,370,000	$ 139,430,000
Contributed capital								0	860,573,000	0
Prudential Insurance
Related Party Transaction [Line Items]
Stock option program plan expense								100,000	100,000	100,000
Deferred compensation program expense								900,000	800,000	600,000
Pension plan expense								1,000,000	1,000,000	1,000,000
Welfare plan expense								$ 2,000,000	2,000,000	2,000,000
Defined contribution plan employer matching contribution percent								4.00%
Defined contribution plan, cost recognized								$ 500,000	500,000	500,000
Affiliated Entity
Related Party Transaction [Line Items]
Corporate Expenses								14,000,000	10,000,000	11,000,000
Accrued interest receivable related to long-term notes	200,000			100,000				200,000	100,000
Revenue related to long-tern notes receivable								700,000	900,000	1,000,000
Interest expense related to loans payable								66,000,000	53,000,000	0
Affiliated Entity | PAIST
Related Party Transaction [Line Items]
Allocated lease expense								3,000,000	4,000,000	4,000,000
Allocated sub-lease rental income								0	0	0
Affiliated Entity | PAD
Related Party Transaction [Line Items]
Commissions and fees								109,000,000	108,000,000	143,000,000
Affiliated Entity | ASTISI and Prudential Investments
Related Party Transaction [Line Items]
Revenue administrative sharing agreement								111,000,000	112,000,000	173,000,000
Affiliated Entity | PGIM
Related Party Transaction [Line Items]
Net investment income								13,000,000	11,000,000	5,000,000
Prudential Financial Joint Ventures
Related Party Transaction [Line Items]
Other long-term investments	111,000,000			102,000,000				111,000,000	102,000,000
Net investment income								9,000,000	$ 5,000,000	100,000
Prudential Financial
Related Party Transaction [Line Items]
Line of credit facility, maximum borrowing capacity	9,000,000,000							9,000,000,000
Dividends						$ 180,000,000	$ 270,000,000
PAI
Related Party Transaction [Line Items]
Contributed capital					$ 8,422,000,000			$ 0		$ 0
Return of capital	$ 650,000,000	$ 200,000,000	$ 100,000,000	$ 1,140,000,000