Pensions and Other Postretirement Benefits (Accumulated Other Comprehensive Loss Pretax Amounts Not Yet Reflected in Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Total	$ 4,701	$ 4,750
Pensions
Defined Benefit Plan Disclosure [Line Items]
Accumulated net actuarial losses	1,542	2,097
Accumulated prior service credit	(26)	(3)
Total	1,516	2,094
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated net actuarial losses	254	505
Accumulated prior service credit	(45)	(45)
Total	$ 209	$ 460