XML 62 R50.htm IDEA: XBRL DOCUMENT v3.10.0.1
Fair Value Measurements - Summary of Available-for-sale Securities Portfolio (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Sep. 30, 2017
Schedule of Available-for-sale Securities [Line Items]          
Original cost $ 335   $ 335   $ 335
Accumulated adjustments, net (38)   (38)   (24)
Adjusted cost [1] 297   297   311
Investment income 2 $ 2 6 [2] $ 7 9 [2]
Net unrealized gain 42   42   35
Realized gains 0 0 4 2 2
Settlement funds     10   2
Disbursements (7) $ (7) (25) $ (19) (27)
Fair value 334   334   332
Available-for-sale Securities [Member]          
Schedule of Available-for-sale Securities [Line Items]          
Adjusted cost 292   292   297
Fair value 334   334   332
Unrealized gain 47   47   35
Unrealized loss (5)   (5)   0
Corporate bond mutual fund [Member]          
Schedule of Available-for-sale Securities [Line Items]          
Adjusted cost 120   120   120
Corporate bond mutual fund, unrealized gain 0   0   1
Corporate bond mutual fund, unrealized loss (5)   (5)   0
Corporate bond mutual fund, Fair value 115   115   121
Equity mutual fund [Member]          
Schedule of Available-for-sale Securities [Line Items]          
Adjusted cost 154   154   168
Equity mutual fund, unrealized gain 47   47   34
Equity mutual fund, unrealized loss 0   0   0
Equity mutual fund, Fair value 201   201   202
Demand Deposits [Member]          
Schedule of Available-for-sale Securities [Line Items]          
Demand deposit $ 18   $ 18   $ 9
[1] The accumulated adjustments include investment income, realized gains, disbursements and settlements recorded in previous periods.
[2] Investment income for the demand deposit includes interest income as well as dividend income transferred from the equity and corporate bond mutual funds.