Pension and Postretirement Benefit Plans (Components of net periodic benefit cost and other information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
United States Qualified and Non-qualified Pension Benefits
Net periodic benefit cost (benefit)
Service cost	$ 64	$ 64	$ 128	$ 127
Interest cost	149	146	299	293
Expected return on plan assets	(261)	(248)	(522)	(496)
Amortization of transition (asset) obligation	0	0	0	0
Amortization of prior service cost (benefit)	1	1	2	3
Amortization of net actuarial (gain) loss	100	118	200	235
Net periodic benefit cost (benefit)	53	81	107	162
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	107	188
International Qualified and Non-qualified Pension Benefits
Net periodic benefit cost (benefit)
Service cost	36	31	72	62
Interest cost	61	62	122	123
Expected return on plan assets	(75)	(73)	(150)	(146)
Amortization of transition (asset) obligation	0	0	(1)	(1)
Amortization of prior service cost (benefit)	(5)	(5)	(9)	(9)
Amortization of net actuarial (gain) loss	40	30	80	60
Net periodic benefit cost (benefit)	57	45	114	89
Settlements, curtailments, special termination benefits and other	0	0	0	0
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	57	45	114	89
Postretirement Benefits
Net periodic benefit cost (benefit)
Service cost	20	20	40	39
Interest cost	22	21	44	43
Expected return on plan assets	(23)	(22)	(45)	(43)
Amortization of transition (asset) obligation	0	0	0	0
Amortization of prior service cost (benefit)	(16)	(18)	(33)	(36)
Amortization of net actuarial (gain) loss	24	28	48	55
Net periodic benefit cost (benefit)	27	29	54	58
Settlements, curtailments, special termination benefits and other	0	0	0	0
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	$ 27	$ 29	$ 54	$ 58