Commitments And Contingencies (Minimum Contractual Obligations) (Details) $ in Millions	Mar. 31, 2020 USD ($)
Long Term Purchase Commitments
Unrecorded Unconditional Purchase Obligation	$ 1,373
Unrecorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	363
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Two	402
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Three	169
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Four	159
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Five	118
Unrecorded Unconditional Purchase Obligation, Due in Rolling after Year Five	162
Recorded Unconditional Purchase Obligation	1,346
Recorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	719
Recorded Unconditional Purchase Obligation, Due in Rolling Year Two	105
Recorded Unconditional Purchase Obligation, Due in Rolling Year Three	33
Recorded Unconditional Purchase Obligation, Due in Rolling Year Four	30
Recorded Unconditional Purchase Obligation, Due in Rolling Year Five	24
Recorded Unconditional Purchase Obligation, Due in Rolling after Year Five	435
TotalUnconditionalPurchaseObligationBalanceSheetAmount	2,719
Total Unconditional Purchase Obligation Balance Sheet Amount One Year After Fiscal Year End	1,082
TotalUnconditionalPurchaseObligationBalanceSheetAmountTwoYearsAfterFiscalYearEnd	507
TotalUnconditionalPurchaseObligationBalanceSheetAmountThreeYearsAfterFiscalYearEnd	202
Total Unconditional Purchase Obligation Balance Sheet Amount Four Years After Fiscal Year End	189
TotalUnconditionalPurchaseObligationBalanceSheetAmountFiveYearsAfterFiscalYearEnd	142
TotalUnconditionalPurchaseObligationBalanceSheetAmountThereafter	597
Unrecorded Unconditional Purchase Obligation Payable in Common Stock [Member] | Maximum [Member]
Long Term Purchase Commitments
Unrecorded Unconditional Purchase Obligation	20
Unrecorded Unconditional Purchase Obligations Payable in Common Stock Per Year [Member] | Maximum [Member]
Long Term Purchase Commitments
Unrecorded Unconditional Purchase Obligation	10
Developer Commitments [Member]
Long Term Purchase Commitments
Unrecorded Unconditional Purchase Obligation	665
Unrecorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	178
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Two	248
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Three	90
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Four	87
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Five	58
Unrecorded Unconditional Purchase Obligation, Due in Rolling after Year Five	4
Marketing
Long Term Purchase Commitments
Unrecorded Unconditional Purchase Obligation	282
Unrecorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	95
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Two	85
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Three	39
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Four	37
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Five	26
Unrecorded Unconditional Purchase Obligation, Due in Rolling after Year Five	0
Senior Notes Interest
Long Term Purchase Commitments
Unrecorded Unconditional Purchase Obligation	134
Unrecorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	38
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Two	20
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Three	19
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Four	19
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Five	19
Unrecorded Unconditional Purchase Obligation, Due in Rolling after Year Five	19
Operating Lease Imputed Interest [Member] [Member]
Long Term Purchase Commitments
Unrecorded Unconditional Purchase Obligation	18
Unrecorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	6
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Two	4
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Three	3
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Four	2
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Five	1
Unrecorded Unconditional Purchase Obligation, Due in Rolling after Year Five	2
Operating Lease [Member]
Long Term Purchase Commitments
Unrecorded Unconditional Purchase Obligation	169
Unrecorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	0
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Two	0
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Three	8
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Four	12
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Five	12
Unrecorded Unconditional Purchase Obligation, Due in Rolling after Year Five	137
Recorded Unconditional Purchase Obligation	224
Recorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	68
Recorded Unconditional Purchase Obligation, Due in Rolling Year Two	54
Recorded Unconditional Purchase Obligation, Due in Rolling Year Three	30
Recorded Unconditional Purchase Obligation, Due in Rolling Year Four	26
Recorded Unconditional Purchase Obligation, Due in Rolling Year Five	20
Recorded Unconditional Purchase Obligation, Due in Rolling after Year Five	26
Other Unrecorded Purchase Obligations [Member]
Long Term Purchase Commitments
Unrecorded Unconditional Purchase Obligation	105
Unrecorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	46
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Two	45
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Three	10
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Four	2
Unrecorded Unconditional Purchase Obligation, Due in Rolling Year Five	2
Unrecorded Unconditional Purchase Obligation, Due in Rolling after Year Five	0
Senior Notes Principal And Interest [Member]
Long Term Purchase Commitments
Recorded Unconditional Purchase Obligation	1,003
Recorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	603
Recorded Unconditional Purchase Obligation, Due in Rolling Year Two	0
Recorded Unconditional Purchase Obligation, Due in Rolling Year Three	0
Recorded Unconditional Purchase Obligation, Due in Rolling Year Four	0
Recorded Unconditional Purchase Obligation, Due in Rolling Year Five	0
Recorded Unconditional Purchase Obligation, Due in Rolling after Year Five	400
Transition And Other Taxes [Member]
Long Term Purchase Commitments
Recorded Unconditional Purchase Obligation	66
Recorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	22
Recorded Unconditional Purchase Obligation, Due in Rolling Year Two	24
Recorded Unconditional Purchase Obligation, Due in Rolling Year Three	3
Recorded Unconditional Purchase Obligation, Due in Rolling Year Four	4
Recorded Unconditional Purchase Obligation, Due in Rolling Year Five	4
Recorded Unconditional Purchase Obligation, Due in Rolling after Year Five	9
License obligations [Member]
Long Term Purchase Commitments
Recorded Unconditional Purchase Obligation	53
Recorded Unconditional Purchase Obligation, Due in Next Rolling Twelve Months	26
Recorded Unconditional Purchase Obligation, Due in Rolling Year Two	27
Recorded Unconditional Purchase Obligation, Due in Rolling Year Three	0
Recorded Unconditional Purchase Obligation, Due in Rolling Year Four	0
Recorded Unconditional Purchase Obligation, Due in Rolling Year Five	0
Recorded Unconditional Purchase Obligation, Due in Rolling after Year Five	$ 0