Reinsurance Level 4 Reinsurance Recoverables (details) - USD ($)	1 Months Ended	2 Months Ended	3 Months Ended	5 Months Ended	6 Months Ended
	Jun. 30, 2018	May 31, 2018	Jun. 30, 2017	May 31, 2018	Jun. 30, 2017	Jun. 01, 2018	Dec. 31, 2017
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Reinsurance Recoverables, Including Reinsurance Premium Paid	$ 30,132,000,000					$ 22,615,000,000	$ 20,785,000,000
Life Insurance Recoveries on Ceded Reinsurance Contracts	126,000,000	$ 194,000,000	$ 260,000,000	$ 546,000,000	$ 584,000,000
Reinsurance Recoverables, Allowance	0						0
Fixed Annuity [Member] | Global Atlantic [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Reinsurance Recoverables, Including Reinsurance Premium Paid	9,500,000,000
Retirement [Member] | Mass Mutual [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Reinsurance Recoverables, Including Reinsurance Premium Paid	8,200,000,000						8,300,000,000
Individual Life [Member] | Prudential [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Reinsurance Recoverables, Including Reinsurance Premium Paid	11,200,000,000						11,100,000,000
Life Annuity Accident and Health Insurance Product Line [Member] | Continuing Operations [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Reinsurance Recoverables, Including Reinsurance Premium Paid	1,346,000,000						1,337,000,000
Life and Annuity Insurance Product Line [Member] | Fixed Annuity [Member] | Global Atlantic [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Reinsurance Recoverables, Including Reinsurance Premium Paid	9,467,000,000
Life and Annuity Insurance Product Line [Member] | Retirement Plans and Individual Life Businesses [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Reinsurance Recoverables, Including Reinsurance Premium Paid	$ 19,319,000,000						$ 19,448,000,000