XML 102 R93.htm IDEA: XBRL DOCUMENT
v3.20.1

New Accounting Standards New Accounting Standards (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2020 | Mar. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Adoption of New Accounting Standard Current Expected Credit Losses | $ (12) | $ 0
Accounting Standards Update 2016-13 [Member] |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Adoption of New Accounting Standard Current Expected Credit Losses | 15 |
Adjustments for New Accounting Pronouncement [Member] |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Adoption of New Accounting Standard Current Expected Credit Losses | $ 55 |

X
- Definition Adoption of New Accounting Standard Current Expected Credit Losses + References No definition available. + Details
Name: | rga_AdoptionofNewAccountingStandardCurrentExpectedCreditLosses
Namespace Prefix: | rga_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201613Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_NewAccountingPronouncementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |