Benefit Obligations (Schedule of Net Periodic Benefit Costs Recognized) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Recognized actuarial (gain) loss		$ (104)	$ 389	$ 306
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		34	28	28
Interest cost		154	170	182
Expected return on plan assets		(223)	(204)	(195)
Amortization of prior service cost		1	2	1
Recognized actuarial (gain) loss		(67)	377	293
Curtailment (gain) loss	(61)	(61)	0	0
Settlement (gain) loss		9	0	0
Special termination benefits		0	0	0
Total		(153)	373	309
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		2	1	1
Interest cost		9	11	13
Expected return on plan assets		0	0	0
Amortization of prior service cost		(12)	1	0
Recognized actuarial (gain) loss		(37)	12	13
Curtailment (gain) loss		0	0	0
Settlement (gain) loss		0	0	0
Special termination benefits		0	0	0
Total		$ (38)	$ 25	$ 27