v3.19.1

Schedule of Valuation and Qualifying Accounts Disclosure (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
SEC Schedule, 12-09, Allowance, Credit Loss [Member] |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Year |  | $ 9 | $ 6 | $ 2
Charged to Expense |  | 5 | 4 | 4
Charged to Other Accounts |  | 1 | 2 | 0
Deductions | [1] | (6) | 3 | 0
Balance at End of Year |  | 9 | 9 | 6
Deferred Tax Asset Valuation Allowance [Member] |  |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at Beginning of Year |  | 1,168 | 1,581 | 1,637
Charged to Expense |  | (168) | (413) | (56)
Charged to Other Accounts |  | 0 | 0 | 0
Deductions | [1] | 0 | 0 | 0
Balance at End of Year |  | $ 1,000 | $ 1,168 | $ 1,581
[1] | Represents write-offs of accounts considered to be uncollectible and previously reserved.

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- Definition Amount of valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
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- Definition Amount of decrease in valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
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