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Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions | Mar. 20, 2020 | Mar. 31, 2020 | Dec. 31, 2019
--- | --- | --- | ---
Debt Instrument [Line Items] |  |  |
Long-term Debt |  | $ 4,432 | $ 3,445
Unamortized Debt Issuance Cost |  | $ 29 | 30
Senior Notes [Member] | 1.625% Senior Notes Due 2029 |  |  |
Debt Instrument [Line Items] |  |  |
Stated interest rate (percent) |  | 1.625% |
Long-term Debt |  | $ 760 | 774
Revolving Credit Facility [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Line of Credit Facility, Interest Rate at Period End |  | 2.25% |
Revolving Credit Facility [Member] | Line of Credit [Member] | Credit Agreement [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Proceeds from Lines of Credit | $ 1,000 |  |
Long-term Debt |  | $ 1,000 | $ 0

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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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