XML 47 R36.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Investments - Securities Available-for-Sale in Gross Unrealized Loss Position (Detail) - USD ($) $ in Millions | Sep. 30, 2017 | Dec. 31, 2016
--- | --- | ---
Corporate and Other Bonds [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | $ 1,216 | $ 2,615
Gross Unrealized Losses, Less than 12 Months | 21 | 61
Estimated Fair Value, 12 Months or Longer | 91 | 254
Gross Unrealized Losses, 12 Months or Longer | 5 | 15
Total Estimated Fair Value | 1,307 | 2,869
Total Gross Unrealized Losses | 26 | 76
States, Municipalities and Political Subdivisions [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 583 | 959
Gross Unrealized Losses, Less than 12 Months | 6 | 32
Estimated Fair Value, 12 Months or Longer | 56 | 23
Gross Unrealized Losses, 12 Months or Longer | 1 | 1
Total Estimated Fair Value | 639 | 982
Total Gross Unrealized Losses | 7 | 33
Residential Mortgage-Backed [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 1,522 | 2,136
Gross Unrealized Losses, Less than 12 Months | 25 | 44
Estimated Fair Value, 12 Months or Longer | 106 | 201
Gross Unrealized Losses, 12 Months or Longer | 3 | 7
Total Estimated Fair Value | 1,628 | 2,337
Total Gross Unrealized Losses | 28 | 51
Commercial Mortgage-Backed [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 378 | 756
Gross Unrealized Losses, Less than 12 Months | 6 | 22
Estimated Fair Value, 12 Months or Longer | 138 | 69
Gross Unrealized Losses, 12 Months or Longer | 7 | 2
Total Estimated Fair Value | 516 | 825
Total Gross Unrealized Losses | 13 | 24
Other Asset-Backed [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 129 | 398
Gross Unrealized Losses, Less than 12 Months | 4 | 5
Estimated Fair Value, 12 Months or Longer | 10 | 24
Total Estimated Fair Value | 139 | 422
Total Gross Unrealized Losses | 4 | 5
Total Asset-Backed [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 2,029 | 3,290
Gross Unrealized Losses, Less than 12 Months | 35 | 71
Estimated Fair Value, 12 Months or Longer | 254 | 294
Gross Unrealized Losses, 12 Months or Longer | 10 | 9
Total Estimated Fair Value | 2,283 | 3,584
Total Gross Unrealized Losses | 45 | 80
U.S. Treasury and Obligations of Government-Sponsored Enterprises [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 67 | 5
Gross Unrealized Losses, Less than 12 Months | 3 |
Estimated Fair Value, 12 Months or Longer | 6 |
Total Estimated Fair Value | 73 | 5
Total Gross Unrealized Losses | 3 |
Foreign Government [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 191 | 108
Gross Unrealized Losses, Less than 12 Months | 4 | 3
Estimated Fair Value, 12 Months or Longer | 5 |
Total Estimated Fair Value | 196 | 108
Total Gross Unrealized Losses | 4 | 3
Total Fixed Maturities Available-for-Sale [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 4,086 | 6,977
Gross Unrealized Losses, Less than 12 Months | 69 | 167
Estimated Fair Value, 12 Months or Longer | 412 | 571
Gross Unrealized Losses, 12 Months or Longer | 16 | 25
Total Estimated Fair Value | 4,498 | 7,548
Total Gross Unrealized Losses | 85 | 192
Equity Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 18 | 12
Gross Unrealized Losses, Less than 12 Months | 1 |
Estimated Fair Value, 12 Months or Longer |  | 13
Gross Unrealized Losses, 12 Months or Longer |  | 4
Total Estimated Fair Value | 18 | 25
Total Gross Unrealized Losses | 1 | 4
Fixed Maturity Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 4,104 | 6,989
Gross Unrealized Losses, Less than 12 Months | 70 | 167
Estimated Fair Value, 12 Months or Longer | 412 | 584
Gross Unrealized Losses, 12 Months or Longer | 16 | 29
Total Estimated Fair Value | 4,516 | 7,573
Total Gross Unrealized Losses | 86 | $ 196
Common Stock [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 2 |
Gross Unrealized Losses, Less than 12 Months | 1 |
Total Estimated Fair Value | 2 |
Total Gross Unrealized Losses | 1 |
Preferred Stock [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Estimated Fair Value, Less than 12 Months | 16 |
Total Estimated Fair Value | $ 16 |

X
- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=l_ForeignGovernmentSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=l_FixedMaturitiesAvailableForSaleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_FixedIncomeSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |