Pensions and Other Postretirement Benefits (Net Periodic Benefit Costs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Defined Contribution Pension [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 13	$ 15
Interest cost	59	52
Expected return on plan assets	(74)	(64)
Amortization of prior service cost	0	0
Amortization of actuarial losses	20	28
Settlement losses (Canada)	0	18
Net periodic pension/other postretirement benefit cost	18	49
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	5
Interest cost	12	12
Expected return on plan assets	0	0
Amortization of prior service cost	(2)	(2)
Amortization of actuarial losses	4	7
Settlement losses (Canada)	0	0
Net periodic pension/other postretirement benefit cost	$ 18	$ 22