Benefit Obligations (Schedule of Net Periodic Benefit Costs Recognized) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012		Jun. 30, 2013	Jun. 30, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8	$ 7		$ 17	$ 14
Interest cost	38	42		77	85
Expected return on plan assets	(56)	(51)	[1]	(112)	(102)	[1]
Recognized actuarial (gain) loss	0	0	[1]	0	0	[1]
Prior service credit	1	0	[1]	1	1
Curtailment (gain) loss	0	0		0	0
Total	(9)	(2)	[1]	(17)	(2)	[1]
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1		2	1
Interest cost	3	3		5	6
Expected return on plan assets	0	0		0	0
Recognized actuarial (gain) loss	0	0	[1]	0	0	[1]
Prior service credit	0	0		0	0
Curtailment (gain) loss	0	0		0	0
Total	$ 4	$ 4	[1]	$ 7	$ 7	[1]

[1] As Adjusted (Note 1)