Medium- And Long-Term Debt (Schedule Of Subordinated Notes Related To Trust Preferred Securities) (Details) (USD $) In Millions, unless otherwise specified			12 Months Ended
	Dec. 31, 2011	Jul. 28, 2011	Dec. 31, 2011 3-Month LIBOR Plus 3.10% [Member]	Dec. 31, 2011 3-Month LIBOR Plus 1.60% [Member]
Maturity Date			Jan. 07, 2012	Jun. 15, 2037
Subordinated Notes Owed to Unconsolidated Subsidiaries	$ 30	$ 83	$ 4	$ 26
Interest Rate			3-month LIBOR plus 3.10%	3-month LIBOR plus 1.60%
Trust Preferred Securities Outstanding	$ 29		$ 4	$ 25
Variable Interest Rate			3.10%	1.60%