Debt Instrument, Deferral Period for Interest Payments

No definition available.

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- Definition

Debt Instrument, Deferral Period for Interest, Period After Which Company Will Be Required to Pay Deferred Interest From Proceeds of Sales of Qualifying Securities

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Put Option, Face Amount Company Can Require be Purchased

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Disposal Group, Including Discontinued Operation, Long-term Debt

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Registration Statement, Term

+ References

No definition available.

+ Details

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- Definition

Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13)(2))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial 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.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.9)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Maximum amount borrowed under the credit facility at any time during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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Debt - Additional Information (Details) - USD ($)			1 Months Ended	12 Months Ended
Debt - Additional Information (Details) - USD ($)	Feb. 08, 2017	Jul. 29, 2016	Apr. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 03, 2017	Mar. 15, 2017
Debt Instrument [Line Items]
Interest expense				$ 316,000,000	$ 327,000,000	$ 346,000,000
Term of registration statement		3 years
Commercial paper outstanding				$ 0
Revolving Credit Facility
Debt Instrument [Line Items]
Facility term				5 years
Credit facility				$ 1,000,000,000.0
Borrowings outstanding under revolving credit facility				0
Commercial Paper
Debt Instrument [Line Items]
Credit facility				$ 1,000,000,000.0
6.1% Notes, due 2041
Debt Instrument [Line Items]
Interest rate				6.10%
Effective interest rate				7.90%
5.375% Notes, due 2017
Debt Instrument [Line Items]
Interest rate				5.375%
8.125% Notes, due 2068
Debt Instrument [Line Items]
Interest rate				8.125%
3 month Libor 2.125% Notes, due 2067 \| LIBOR
Debt Instrument [Line Items]
Interest rate			4.39%
Variable interest rate			2.125%	2.125%
Fixed interest rate from interest rate swap			4.39%
7.875% Notes, due 2042
Debt Instrument [Line Items]
Interest rate				7.875%
4.3% Notes, due 2043
Debt Instrument [Line Items]
Interest rate				4.30%
Senior Notes \| 5.375% Notes, due 2017
Debt Instrument [Line Items]
Interest rate								5.375%
Debt repaid								$ 416,000,000
Junior Subordinated Debentures
Debt Instrument [Line Items]
Interest deferral period				10 years
Interest deferral period after which company will be required to pay deferred interest from proceeds of sales of qualifying securities				5 years
Redemption price				100.00%
Principal amount which the company can require the counterparty to purchase as part of put option agreement				$ 500,000,000
Debt issuance	$ 500,000,000
Run-Off Life and Annuity Business \| Discontinued Operations, Held-for-sale
Debt Instrument [Line Items]
Long-term debt				$ 142,000,000	$ 142,000,000		$ 142,000,000