Pension Plans, Retirement Benefits and Savings Plans (details) (USD $) In Millions	1 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Aug. 31, 2011	Sep. 30, 2011 Pension Plans [Member]	Sep. 30, 2010 Pension Plans [Member]	Sep. 30, 2011 Pension Plans [Member]	Sep. 30, 2010 Pension Plans [Member]	Sep. 30, 2011 Postretirement Benefit Plans [Member]	Sep. 30, 2010 Postretirement Benefit Plans [Member]	Sep. 30, 2011 Postretirement Benefit Plans [Member]	Sep. 30, 2010 Postretirement Benefit Plans [Member]
Defined benefit plan disclosure
Service cost		$ 25	$ 24	$ 74	$ 72	$ 1	$ 1	$ 1	$ 1
Interest cost on benefit obligation		33	32	101	96	3	4	10	11
Expected return on plan assets		(46)	(46)	(137)	(138)		(1)	(1)	(1)
Amortization of unrecognized prior service benefit					(2)
Amortization of unrecognized net actuarial loss		20	15	58	45
Net periodic benefit cost, net benefit expense		32	25	96	73	4	4	10	11
Company contribution to qualified domestic pension plan	$ 35