Investments (Schedule Of Default Assumptions By Moody's Rating Category) (Details)	12 Months Ended
	Dec. 31, 2011
Investment Grade [Member] | Minimum [Member] | Aaa-Baa [Member]
Financing Receivable, Recorded Investment [Line Items]
1-in-100 Year Default Rate	0.00%
Historical Mean Default Rate	0.00%
Investment Grade [Member] | Maximum [Member] | Aaa-Baa [Member]
Financing Receivable, Recorded Investment [Line Items]
1-in-100 Year Default Rate	1.40%
Historical Mean Default Rate	0.30%
Below Investment Grade [Member] | Ba [Member]
Financing Receivable, Recorded Investment [Line Items]
1-in-100 Year Default Rate	4.80%
Historical Mean Default Rate	1.10%
Below Investment Grade [Member] | B [Member]
Financing Receivable, Recorded Investment [Line Items]
1-in-100 Year Default Rate	12.80%
Historical Mean Default Rate	3.40%
Below Investment Grade [Member] | Caa-C [Member]
Financing Receivable, Recorded Investment [Line Items]
1-in-100 Year Default Rate	53.50%
Historical Mean Default Rate	13.90%