Quarterly report pursuant to Section 13 or 15(d)

Marketable Securities (Details)

v3.19.1
Marketable Securities (Details) - USD ($)
$ in Millions
Mar. 31, 2019
Sep. 30, 2018
Schedule of Marketable Securities [Line Items]    
Available-for-sale - current $ 51 $ 144
Available-for-sale - noncurrent 35 35
Marketable securities - current 195 311
Marketable securities - noncurrent 36 35
Corporate bonds and notes [Member]    
Schedule of Marketable Securities [Line Items]    
Available-for-sale - current 51 144
Available-for-sale - noncurrent 0 0
Auction rate securities [Member]    
Schedule of Marketable Securities [Line Items]    
Available-for-sale - current 0 0
Available-for-sale - noncurrent 35 35
Equity securities [Member]    
Schedule of Marketable Securities [Line Items]    
Marketable securities - current 144 167
Marketable securities - noncurrent $ 1 $ 0