Benefit Obligations (Schedule of Net Periodic Benefit Costs Recognized) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014		Sep. 30, 2015	Sep. 30, 2014
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 3		$ 10	$ 9
Interest cost	34	41		105	126
Expected return on plan assets	(53)	(54)		(158)	(162)
Recognized actuarial (gain) loss	0	0		0	0
Amortization of prior service cost (credit), net	0	0		0	0
Special termination benefit	1	0		2	0
Total	(14)	(10)		(41)	(27)
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0		1	1
Interest cost	1	1		2	3
Expected return on plan assets	0	0		0	0
Recognized actuarial (gain) loss	0	0		1	0
Amortization of prior service cost (credit), net	0	(21)	[1]	0	(62)	[1]
Special termination benefit	0	0		0	0
Total	$ 1	$ (20)		$ 4	$ (58)

[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.