Pension and Postretirement Benefit Plans (Components of net periodic benefit cost and other information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
United States Qualified and Non-qualified Pension Benefits
Net periodic benefit cost (benefit)
Service cost	$ 64	$ 64	$ 192	$ 191
Interest cost	150	147	449	440
Expected return on plan assets	(262)	(248)	(784)	(744)
Amortization of transition (asset) obligation	0	0	0	0
Amortization of prior service cost (benefit)	1	1	3	4
Amortization of net actuarial (gain) loss	100	117	300	352
Net periodic benefit cost (benefit)	53	81	160	243
Settlements, curtailments, special termination benefits and other	0	0	0	26
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	53	81	160	269
International Qualified and Non-qualified Pension Benefits
Net periodic benefit cost (benefit)
Service cost	37	31	109	93
Interest cost	61	61	183	184
Expected return on plan assets	(75)	(73)	(225)	(219)
Amortization of transition (asset) obligation	0	0	(1)	(1)
Amortization of prior service cost (benefit)	(4)	(4)	(13)	(13)
Amortization of net actuarial (gain) loss	39	30	119	90
Net periodic benefit cost (benefit)	58	45	172	134
Settlements, curtailments, special termination benefits and other	0	0	0	0
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	58	45	172	134
Postretirement Benefits
Net periodic benefit cost (benefit)
Service cost	20	19	60	58
Interest cost	22	22	66	65
Expected return on plan assets	(22)	(21)	(67)	(64)
Amortization of transition (asset) obligation	0	0	0	0
Amortization of prior service cost (benefit)	(16)	(18)	(49)	(54)
Amortization of net actuarial (gain) loss	24	27	72	82
Net periodic benefit cost (benefit)	28	29	82	87
Settlements, curtailments, special termination benefits and other	0	0	0	0
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	$ 28	$ 29	$ 82	$ 87