Related Party Transactions (Narrative) (Details) - USD ($)	3 Months Ended							9 Months Ended		12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Investment expense	$ 5,332,000				$ 3,883,000			$ 14,685,000	$ 11,226,000
Commissions and fees	527,152,000				550,592,000			1,559,874,000	1,653,225,000
Other invested assets	427,504,000			$ 348,541,000				427,504,000		$ 348,541,000
Net investment income	149,367,000				103,164,000			406,408,000	300,035,000
Fee income from revenue sharing agreement	120,927,000				93,320,000			345,520,000	291,460,000
Contributed capital								0		0
Prudential Insurance
Related Party Transaction [Line Items]
Stock option program plan expense	0.0				0			100,000	100,000
Deferred compensation program expense	0.0				200,000			500,000	500,000
Pension plan expense	500,000				400,000			2,000,000	1,000,000
Welfare plan expense	500,000				500,000			$ 2,000,000	2,000,000
Defined contribution plan employer matching contribution percent								4.00%
Defined contribution plan, cost recognized	200,000				200,000			$ 700,000	500,000
Affiliated Entity
Related Party Transaction [Line Items]
Accrued interest receivable related to long-term notes receivables	200,000			300,000				200,000		300,000
Revenue related to long-term notes receivable	100,000				100,000			(100,000)	300,000
Interest expense related to loans payable	38,000,000				14,000,000			78,000,000	44,000,000
Affiliated Entity | PAD
Related Party Transaction [Line Items]
Commissions and fees	24,000,000				32,000,000			74,000,000	91,000,000
Affiliated Entity | ASTISI and PGIM Investments
Related Party Transaction [Line Items]
Fee income from revenue sharing agreement	24,000,000				26,000,000			72,000,000	80,000,000
Affiliated Entity | PGIM
Related Party Transaction [Line Items]
Investment expense	4,000,000				3,000,000			12,000,000	9,000,000
Prudential Financial Joint Venture
Related Party Transaction [Line Items]
Other invested assets	346,000,000			228,000,000				346,000,000		$ 228,000,000
Net investment income	3,000,000				2,000,000			11,000,000	4,000,000
Prudential Financial
Related Party Transaction [Line Items]
Company's share of corporate expenses (benefits)	4,000,000				4,000,000			12,000,000	$ 12,000,000
Line of credit facility, maximum borrowing capacity	9,000,000,000							$ 9,000,000,000
PAI
Related Party Transaction [Line Items]
Return of capital	$ 245,000,000	$ 247,000,000	$ 245,000,000	$ 225,000,000	$ 250,000,000	$ 250,000,000	$ 300,000,000