v2.4.0.6

Segment Reporting (Narrative) (Details)	6 Months Ended
	Jun. 30, 2012 segments
Segment Reporting Information [Line Items]
Reportable Segments	3
Insurance [Member]
Segment Reporting Information [Line Items]
Number of States in which Glencoe Operates	49

X

- Definition

Disclosure of the number of segments reported by the entity.

+ References

No definition available.

+ Details

Name:	rnr_NumberOfReportableSegments
Namespace Prefix:	rnr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration