Benefit Obligations (Schedule of Net Periodic Benefit Costs Recognized) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014		Jun. 30, 2015	Jun. 30, 2014
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 3		$ 6	$ 6
Interest cost	36	43		71	85
Expected return on plan assets	(53)	(54)		(105)	(108)
Recognized actuarial (gain) loss	0	0		0	0
Amortization of prior service cost (credit), net	0	0		0	0
Special termination benefit	0	0		1	0
Total	(14)	(8)		(27)	(17)
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1		1	1
Interest cost	0	0		1	2
Expected return on plan assets	0	0		0	0
Recognized actuarial (gain) loss	1	0		1	0
Amortization of prior service cost (credit), net	0	(22)	[1]	0	(41)	[1]
Special termination benefit	0	0		0	0
Total	$ 2	$ (21)		$ 3	$ (38)

[1] Primarily related to the elimination of eligibility for all current and future US employees to participate in the Company's US postretirement health care plan.