Postretirement Plans (Narrative) (Details) (Pension Plans, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Pension Curtailment charge	$ 338	$ 20
Defined Benefit Plan, Benefit Obligation Discount Rate	4.50%		4.80%
defined benefit plan changes [Member]
Defined Benefit Plan Disclosure [Line Items]
Union and nonunion participants transitioned to defined contribution plan	100,000
Pension Curtailment charge	334
Pension Benefit Plans, Net Actuarial Gain, before Tax recorded in Other Comprehensive Income	966
Defined Benefit Plan Curtailment	1,988
Defined Benefit Plan, Net Actuarial Gain (Loss)	$ 1,022