Information About Segments of Business Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item
Assets	$ 18,810.6	$ 17,101.6
General Insurance Group [Member]
Segment Reporting, Asset Reconciling Item
Assets	15,541.8	14,523.0
Title Insurance Segment [Member]
Segment Reporting, Asset Reconciling Item
Assets	1,384.2	1,314.3
RFIG Run-off Business [Member]
Segment Reporting, Asset Reconciling Item
Assets	942.9	978.7
Total Company Segments [Member]
Segment Reporting, Asset Reconciling Item
Assets	17,868.9	16,816.1
All Other Segments [Member]
Segment Reporting, Asset Reconciling Item
Assets	1,293.1	760.5
Intersegment Elimination [Member]
Segment Reporting, Asset Reconciling Item
Assets	$ (351.4)	$ (475.0)