Related Party Transactions (Affiliated Asset Transfers) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Related Party Transaction [Line Items]
Realized investment (gains) losses, net	$ (245,974)	$ (537,267)	$ (4,379,429)	$ (2,773,701)
Affiliated Entity | Prudential Insurance January 2019 Sale
Related Party Transaction [Line Items]
Fair Value	20,504		20,504
Book Value	20,781		20,781
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			(277)
Affiliated Entity | Prudential Insurance February 2019 Sale
Related Party Transaction [Line Items]
Fair Value	97,953		97,953
Book Value	98,506		98,506
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			(554)
Affiliated Entity | Prudential Insurance March 2019 Purchase
Related Party Transaction [Line Items]
Fair Value	141,476		141,476
Book Value	141,476		141,476
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			7,776
Affiliated Entity | Prudential Insurance April 2019 Purchase
Related Party Transaction [Line Items]
Fair Value	4,300		4,300
Book Value	4,300		4,300
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			0
Affiliated Entity | Prudential Retirement Insurance & Annuity April 2019 Purchase
Related Party Transaction [Line Items]
Fair Value	1,258		1,258
Book Value	1,258		1,258
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			0
Affiliated Entity | Pruco Life April 2019 Purchase
Related Party Transaction [Line Items]
Fair Value	14,525		14,525
Book Value	14,525		14,525
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			0
Affiliated Entity | Prudential Insurance June 2019 - Transfer Out
Related Party Transaction [Line Items]
Fair Value	23,066		23,066
Book Value	23,002		23,002
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			64
Affiliated Entity | Prudential Insurance June 2019 - Transfer In
Related Party Transaction [Line Items]
Fair Value	19,919		19,919
Book Value	19,919		19,919
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			0
Affiliated Entity | Prudential Insurance August 2019 - Sale
Related Party Transaction [Line Items]
Fair Value	66,346		66,346
Book Value	64,735		64,735
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			1,611
Affiliated Entity | Prudential Insurance August 2019 - Sale
Related Party Transaction [Line Items]
Fair Value	106,307		106,307
Book Value	104,733		104,733
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			1,574
Affiliated Entity | Prudential Insurance November 2019 Sale
Related Party Transaction [Line Items]
Fair Value	2,289		2,289
Book Value	2,362		2,362
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			(73)
Affiliated Entity | Prudential Insurance November 2019 Sale
Related Party Transaction [Line Items]
Fair Value	6,517		6,517
Book Value	8,550		8,550
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			(2,033)
Affiliated Entity | Prudential Insurance December 2019 Purchase
Related Party Transaction [Line Items]
Fair Value	5,271		5,271
Book Value	5,271		5,271
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			0
Affiliated Entity | Prudential Insurance December 2019 Purchase
Related Party Transaction [Line Items]
Fair Value	85,261		85,261
Book Value	85,261		85,261
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			0
Affiliated Entity | Prudential Insurance December 2019 Sale
Related Party Transaction [Line Items]
Fair Value	21,425		21,425
Book Value	20,628		20,628
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			797
Affiliated Entity | Prudential International Insurance Service Company March 2020 - Purchase
Related Party Transaction [Line Items]
Fair Value	107,014		107,014
Book Value	107,014		107,014
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			0
Affiliated Entity | Prudential Insurance March 2020 Purchase
Related Party Transaction [Line Items]
Fair Value	258,885		258,885
Book Value	258,885		258,885
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			0
Affiliated Entity | Prudential Insurance April 2020 Purchase
Related Party Transaction [Line Items]
Fair Value	91,131		91,131
Book Value	91,131		91,131
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			0
Affiliated Entity | Prudential Insurance June 2020 Sale
Related Party Transaction [Line Items]
Fair Value	65,646		65,646
Book Value	57,699		57,699
APIC, Net of Tax Increase/(Decrease)	0		0
Realized investment (gains) losses, net			7,947
Affiliated Entity | Gibraltar life insurance company June 2020 Purchase
Related Party Transaction [Line Items]
Fair Value	222,091		222,091
Book Value	222,091		222,091
APIC, Net of Tax Increase/(Decrease)	$ 0		0
Realized investment (gains) losses, net			$ 0