Business Segment Information Business Segment Information (Restructuring Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ 20	$ 110
Paid in cash	$ 6	53	25
Non-cash portion			46
Implementation Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs		9	19
Paid in cash	0	9	19
Non-cash portion			0
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs		11	45
Paid in cash	6	44	6
Non-cash portion			0
Benefits Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0	26
Paid in cash	0	0	0
Non-cash portion			26
Property, Plant, and Equipment Impairments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs		0	20
Paid in cash	$ 0	$ 0	0
Non-cash portion			$ 20