Fair Value Measurements Fair Value Measurements - Assets Measured at Fair Value on Nonrecurring Basis (Details) (Fair Value, Measurements, Nonrecurring, USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, plant, and equipment, fair value	$ 0	$ 1
Impairment of long-lived assets held-for-use	0	8
Other assets, fair value	0	0
Other asset impairment charges	$ 11	$ 0