Pension and Postretirement Benefit Plans (Components of net periodic benefit cost and other information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
United States Qualified and Non-qualified Pension Benefits
Net periodic benefit cost (benefit)
Service cost	$ 64	$ 63
Interest cost	150	147
Expected return on plan assets	(261)	(248)
Amortization of transition (asset) obligation	0	0
Amortization of prior service cost (benefit)	1	2
Amortization of net actuarial (gain) loss	100	117
Net periodic benefit cost (benefit)	54	81
Settlements, curtailments, special termination benefits and other	0	26
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	54	107
International Qualified and Non-qualified Pension Benefits
Net periodic benefit cost (benefit)
Service cost	36	31
Interest cost	61	61
Expected return on plan assets	(75)	(73)
Amortization of transition (asset) obligation	(1)	(1)
Amortization of prior service cost (benefit)	(4)	(4)
Amortization of net actuarial (gain) loss	40	30
Net periodic benefit cost (benefit)	57	44
Settlements, curtailments, special termination benefits and other	0	0
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	57	44
Postretirement Benefits
Net periodic benefit cost (benefit)
Service cost	20	19
Interest cost	22	22
Expected return on plan assets	(22)	(21)
Amortization of transition (asset) obligation	0	0
Amortization of prior service cost (benefit)	(17)	(18)
Amortization of net actuarial (gain) loss	24	27
Net periodic benefit cost (benefit)	27	29
Settlements, curtailments, special termination benefits and other	0	0
Net periodic benefit cost (benefit) after settlements, curtailments, special termination benefits and other	$ 27	$ 29