Retirement Benefits and Trusteed Assets [Details] (USD $) In Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2011	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2011
Pension Benefits [Member]
Components of net pension cost
Service cost		$ 18	$ 16	$ 37	$ 32
Interest cost		50	51	101	101
Expected return on plan assets		(61)	(65)	(123)	(129)
Amortization of:
Net actuarial loss		33	25	66	50
Prior service cost		1	1	2	2
Special termination benefits		2		2
Net periodic benefit cost		43	28	85	56
Retirement Benefits and Trusteed Assets (Textuals) [Abstract]
Company's contribution to pension plans	200
Other Postretirement Benefits
Components of net pension cost
Service cost		17	14	34	30
Interest cost		31	31	62	63
Expected return on plan assets		(23)	(18)	(47)	(37)
Amortization of:
Net actuarial loss		15	13	30	27
Prior service cost		(6)	(1)	(13)	(2)
Net transition liability			1	1	1
Net periodic benefit cost		34	40	67	82
Retirement Benefits and Trusteed Assets (Textuals) [Abstract]
Company's contribution to other postretirement benefits plans	81
Expected contribution to other postretirement benefit plans						$ 90