XML 166 R137.htm IDEA: XBRL DOCUMENT v3.6.0.2
Pension and Other Postretirement Benefits - Schedule of One-Percentage Point Change in Assumed Rates of Health Care Cost Trend Rates (Detail)
$ in Millions
12 Months Ended
Dec. 31, 2016
USD ($)
Compensation and Retirement Disclosure [Abstract]  
Effect on other postretirement benefit obligations, 1% increase $ 44
Effect on total of service and interest cost components, 1% increase 4
Effect on other postretirement benefit obligations, 1% decrease (40)
Effect on total of service and interest cost components, 1% decrease $ (3)