Benefit Obligations (Schedule of Net Periodic Benefit Costs Recognized) (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 Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 9	$ 9	$ 26
Interest cost	41	39	126	116
Expected return on plan assets	(54)	(57)	(162)	(169)
Amortization of prior service cost (credit), net	0	0	0	1
Total	(10)	(9)	(27)	(26)
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1	2
Interest cost	1	3	3	8
Expected return on plan assets	0	0	0	0
Amortization of prior service cost (credit), net	(21)	0	(62)	0
Total	$ (20)	$ 3	$ (58)	$ 10