XML 178 R140.htm IDEA: XBRL DOCUMENT v3.8.0.1
Employee Benefit Plans (Pension Plans with Projected Benefit Obligations in Excess of Fair Value of Plan Assets) (Details) - Pension Plans - USD ($)
$ in Millions
Dec. 31, 2017
Dec. 31, 2016
Pension Plans with Benefit Obligations in Excess of the Fair Value of Plan Assets    
Projected benefit obligation $ 3,676 $ 566
Accumulated benefit obligation 3,663 552
Fair value of plan assets 3,091 56
Accumulated benefit obligation $ 3,953 $ 3,696