Segment Information (Net Premiums Earned By Geographic Region) (Details)

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Segment Reporting Information [Line Items]

Net Premiums Earned by Geographic Region

	North America				Asia  Pacific/Far East		Latin America
Years Ended December 31			Europe(1)
2014	58	%	16	%	16	%	10	%
2013	58	%	17	%	16	%	9	%
2012	60	%	17	%	16	%	7	%

North America [Member]

Segment Reporting Information [Line Items]

Percentage of net premiums earned by geographic region

58.00%

58.00%

60.00%

Europe [Member]

Segment Reporting Information [Line Items]

Percentage of net premiums earned by geographic region

16.00%

^[1]

17.00%

^[1]

17.00%

^[1]

Asia Pacific and Far East [Member]

Segment Reporting Information [Line Items]

Percentage of net premiums earned by geographic region

16.00%

16.00%

16.00%

Latin America [Member]

Segment Reporting Information [Line Items]

Percentage of net premiums earned by geographic region

10.00%

9.00%

7.00%

[1] (1) Europe includes Eurasia and Africa region.