XML 98 R69.htm IDEA: XBRL DOCUMENT v3.4.0.3
Benefit Plans Components of Net Periodic Benefit Cost (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Mar. 31, 2016
Mar. 31, 2015
Pension Benefits        
Defined Benefit Plan Disclosure        
Service cost $ 34 $ 31 $ 66 $ 65
Interest cost 142 137 282 270
Expected return on plan assets (112) (109) (223) (218)
Amortization of prior service cost (5) (6) (11) (11)
Recognized net actuarial loss 82 81 155 150
Total net periodic benefit cost as actuarially determined 141 134 269 256
Amount capitalized due to actions of regulator (71) (63) (129) (114)
Total net periodic benefit cost 70 71 140 142
Other Post-retirement Benefits        
Defined Benefit Plan Disclosure        
Service cost 4 3 8 8
Interest cost 8 7 15 15
Expected return on plan assets 0 0 0 0
Amortization of prior service cost (2) (1) (3) (3)
Recognized net actuarial loss 1 2 3 4
Total net periodic benefit cost as actuarially determined 11 11 23 24
Amount capitalized due to actions of regulator 0 0 0 0
Total net periodic benefit cost $ 11 $ 11 $ 23 $ 24