Leases (Supplemental Balance Sheet Information Related To Leases) (Details) $ in Millions	Sep. 30, 2019 USD ($)
Supplemental Balance Sheet Information Related To Leases [Line Items]
Operating right-of-use assets	$ 196
Finance right-of-use assets	170
Operating lease liabilities	203
Finance lease liabilities	$ 161
Operating leases, Weighted-average remaining lease term	7 years 7 months 9 days
Operating leases, Weighted-average discount rate	8.26%
Finance lease, Weighted-average remaining lease term	8 years 10 months 9 days
Finance lease, Weighted-average discount rate	7.97%
Other Current Liabilities [Member]
Supplemental Balance Sheet Information Related To Leases [Line Items]
Finance lease liabilities, Current	$ 28
Current operating lease liabilities	44
Other Noncurrent Liabilities [Member]
Supplemental Balance Sheet Information Related To Leases [Line Items]
Financed lease liabilities, Noncurrent	133
Noncurrent operating lease liabilities	$ 159

Supplemental Balance Sheet Information Related To Leases [Line Items]

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Present value of lessee's discounted obligation for lease payments from finance lease.

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