Commitments And Contingencies (Narrative) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Unrecorded Unconditional Purchase Obligation	$ 2,414
Amount of potential cash payments that could result from unrecognized tax benefits	87
Unrecorded Unconditional Purchase Obligation Payable in Common Stock Per Year | Maximum
Loss Contingencies [Line Items]
Unrecorded Unconditional Purchase Obligation	10
Unrecorded Unconditional Purchase Obligation Payable in Common Stock | Maximum
Loss Contingencies [Line Items]
Unrecorded Unconditional Purchase Obligation	$ 32