Retirement Benefits (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Amortization of:
Defined contribution plans cost	$ 297	$ 288	$ 291
Pension Benefits
Components of Net Periodic Benefit Cost (Table Amounts) [Abstract]
Service cost	520	531	547
Interest cost	1,223	1,212	1,180
Expected return on plan assets	(1,690)	(1,517)	(1,366)
Amortization of:
Prior service cost (credit)	23	35	34
Net loss from previous years	162	206	289
Other			21
Net periodic benefit cost	238	467	705
Medical and Life Benefits
Components of Net Periodic Benefit Cost (Table Amounts) [Abstract]
Service cost	32	34	34
Interest cost	114	117	124
Expected return on plan assets	(62)	(56)	(48)
Amortization of:
Prior service cost (credit)	(51)	(51)	(51)
Net loss from previous years	17	18	19
Other	(6)
Net periodic benefit cost	$ 44	$ 62	$ 78