Pension And Other Postretirement Benefits (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Pension Benefits [Member]
Service cost	$ 10	$ 8	$ 27	$ 26
Interest cost	27	28	80	83
Expected return on plan assets	(32)	(30)	(96)	(88)
Amortization of prior service cost			(1)
Amortization of net actuarial loss	11	11	35	32
Plan amendment				1
Net periodic benefit cost	16	17	45	54
Other Postretirement Benefits [Member]
Service cost	1	1	4	4
Interest cost	10	10	28	29
Expected return on plan assets	(5)	(4)	(14)	(12)
Amortization of prior service cost	(1)	(1)	(3)	(3)
Amortization of net actuarial loss	3	3	9	9
Termination benefits			1	5
Net periodic benefit cost	$ 8	$ 9	$ 25	$ 32