Securities in an Unrealized Loss Position (Narrative) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Preferred Stocks [Member]
Number of Securites	6
Aggregate fair value	$ 69
Gross unrealized loss	15
Number of investment-grade, available for sale equity securities, continuous unrealized loss position	4
Number of available for sale equity securities non investment grade continuous unrealized loss position aggregate loss	2
Non-investment grade aggregate fair value	9
Non-investment grade gross unrealized loss	5
Number of available for sale equity securities, non investment grade, continuous unrealized loss position aggregate loss, demonstrating improved fundamentals	1
Common Stocks [Member]
Number of Securites	4
Aggregate fair value	47
Gross unrealized loss	$ 3