Benefit Obligations (Schedule of Nonqualified Pension Plans Funded with Nonqualified Trusts) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Noncurrent Other assets, consisting of insurance contracts	$ 62	$ 66
Current Other liabilities	541	475
Benefit obligations	1,175	1,602
Nonqualified Trust Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Marketable securities, at fair value	41	53
Nonqualified Pension Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent Other assets, consisting of insurance contracts	62	66
Current Other liabilities	22	22
Benefit obligations	247	264
Nonqualified Pension Obligations [Member] | Nonqualified Trust Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Marketable securities, at fair value	$ 41	$ 53