Pension and Other Postretirement Benefit Plans (Components of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Amortization:
Curtailment gain	$ 0	$ 0	$ (52)
United States Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	2
Interest cost	167	162	178
Expected return on plan assets	(193)	(191)	(194)
Amortization:
Actuarial loss	43	62	46
Prior service cost (credit)	(3)	(3)	(3)
Curtailment gain	0	0	0
Settlement loss	0	3	5
Net periodic benefit cost	16	35	34
Foreign Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	6	6
Interest cost	22	17	20
Expected return on plan assets	(16)	(10)	(11)
Amortization:
Actuarial loss	5	6	4
Prior service cost (credit)	1	1	1
Curtailment gain	0	0	0
Settlement loss	4	1	3
Net periodic benefit cost	21	21	23
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	4	5
Interest cost	24	18	21
Expected return on plan assets	0	0	0
Amortization:
Actuarial loss	0	1	1
Prior service cost (credit)	(36)	(39)	(42)
Curtailment gain	0	0	(52)
Settlement loss	0	0	0
Net periodic benefit cost	$ (9)	$ (16)	$ (67)