Consolidated Statements of Comprehensive Income (Parentheticals) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Actuarial loss arising during the period, income tax	$ 48	$ 46	$ 16
Prior service costs arising during the period, income tax			1
Reclassification of losses to net benefit cost, income tax	6	10	9
Reclassification of prior service costs to net benefit cost, income tax	1	2	2
Net derivative instrument gains (losses) arising during the period, income tax	2	1
Reclassification of realized derivative losses to net income, income tax	$ 2	$ 1	$ 3