Acquisitions By Major Class (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Other disclosures
Pre-tax acquisition and integration costs	$ 1	$ 4
Customer Relationships | Multi-period excess earnings method
Identifiable intangible assets
Fair Value	$ 24
Estimated Remaining Useful Life	15 years
Trade names | Relief-from-royalty method
Identifiable intangible assets
Fair Value	$ 4
Estimated Remaining Useful Life	11 years
Noncompetition Agreements | Income Approach
Identifiable intangible assets
Fair Value	$ 1
Estimated Remaining Useful Life	3 years
Penford And Kerr Acquisitions
Other disclosures
Pre-tax acquisition and integration costs	$ 1	$ 4