Line items represent reporting concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 12
-Sentence Column A

Investments (Narrative) (Details) $ in Millions	12 Months Ended
Investments (Narrative) (Details) $ in Millions	Dec. 31, 2018 USD ($) security item	Dec. 31, 2017 USD ($) security item	Dec. 31, 2016 USD ($)
Investment [Line Items]
Increase (decrease) in gross AFS securities unrealized losses	$ 2
Unrealized gain (loss), trading securities	$ (58)	$ 7	$ (3)
Number of partnerships in alternative investment portfolio \| item	237	224
Alternative investments as a percentage of overall invested assets	1.00%	1.00%
Fair value of collateral received that we are permitted to sell or re-pledge	$ 537
Securities that have been re-pledged	378
Investment commitments	2,100
Investment commitments for limited partnerships	843
Investment commitments for mortgage loans on real estate	804
Investment commitments for private placements	$ 476
OTTI in OCI			55
Change in DAC, VOBA, DSI and DFEL			$ 12
Commercial [Member]
Investment [Line Items]
Number of impaired loans \| security	0	3
Impaired financing receivable, principal balance		$ 11
Impaired financing receivable, allowance		3
Impaired financing receivable, carrying amount		8
Residential [Member]
Investment [Line Items]
Number of impaired loans \| security	0
Maximum [Member]
Investment [Line Items]
OTTI in OCI	$ 1	1
Maximum [Member] \| Residential [Member]
Investment [Line Items]
Impaired financing receivable, allowance	1
Federal Home Loan Mortgage Corporation [Member] \| Invested Assets [Member]
Investment [Line Items]
Fair value	$ 1,400	$ 1,300
Concentration risk, percentage	1.00%	1.00%
Federal National Mortgage Association [Member] \| Invested Assets [Member]
Investment [Line Items]
Fair value	$ 1,300	$ 1,000
Concentration risk, percentage	1.00%	1.00%
Consumer Non-Cyclical Industry [Member] \| Invested Assets [Member]
Investment [Line Items]
Fair value	$ 14,500	$ 15,000
Concentration risk, percentage	13.00%	13.00%
Financial Service [Member] \| Invested Assets [Member]
Investment [Line Items]
Fair value	$ 14,200
Concentration risk, percentage	12.00%
Utilities Industry [Member] \| Invested Assets [Member]
Investment [Line Items]
Fair value		$ 14,300
Concentration risk, percentage		13.00%
Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| California [Member] \| Commercial [Member]
Investment [Line Items]
Concentration risk, percentage	23.00%	21.00%
Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| California [Member] \| Residential [Member]
Investment [Line Items]
Concentration risk, percentage	34.00%
Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| Texas [Member] \| Commercial [Member]
Investment [Line Items]
Concentration risk, percentage	12.00%	12.00%
Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| FLORIDA \| Residential [Member]
Investment [Line Items]
Concentration risk, percentage	19.00%
Corporate Bonds [Member]
Investment [Line Items]
Percentage of fair value rated as investment grade		96.00%
Amortized cost of portfolio rated below investment grade	$ 3,200	$ 3,500
Fair value of portfolio rated below investment grade	$ 3,000	$ 3,500
MBS [Member]
Investment [Line Items]
Severity of second lien loans	100.00%
Severity of first lien loans	30.00%