Pensions and Other Postretirement Benefits (Net Periodic Benefit Costs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11	$ 16	$ 38	$ 45
Interest cost	54	56	172	162
Expected return on plan assets	(76)	(72)	(224)	(211)
Amortization of actuarial losses	18	16	58	76
Amortization of prior service cost	(1)	0	(2)	0
Settlement losses (Canada)	2	0	7	18
Net periodic pension/other postretirement benefit cost	8	16	49	90
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	5	12	15
Interest cost	10	12	35	37
Amortization of actuarial losses	1	7	8	21
Amortization of prior service cost	(2)	(2)	(7)	(7)
Net periodic pension/other postretirement benefit cost	$ 12	$ 22	$ 48	$ 66