v3.20.1

Debt (Narrative) (Details) - USD ($) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2020 | Dec. 31, 2019
Debt Instrument [Line Items] |  |
Debt Instrument, Face Amount | $ 4,750,000,000 | $ 4,750,000,000
Long term debt | 4,706,386,000 | 4,706,075,000
Revolving Credit Facility [Member] |  |
Debt Instrument [Line Items] |  |
Long term debt |  | 0
Commercial Paper [Member] |  |
Debt Instrument [Line Items] |  |
Line of Credit Facility, Maximum Borrowing Capacity | $ 1,000,000,000.0 |
Commercial Paper [Member] | Maximum [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Term | 397 days |
Three Point Nine Five Percentage Notes Due Two Thousand Fifty [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Face Amount | $ 500,000,000 | 500,000,000
Debt Instrument, Interest Rate, Stated Percentage | 3.95% |
4.85% Notes Due 2049 [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Face Amount | $ 500,000,000 | 500,000,000
Debt Instrument, Interest Rate, Stated Percentage | 4.85% |
Senior Notes [Member] | Revolving Credit Facility [Member] |  |
Debt Instrument [Line Items] |  |
Line of Credit Facility, Maximum Borrowing Capacity | $ 1,000,000,000.0 |
Unused commitment fee | 0.125% |
Long term debt | $ 0 |
Obligation for letters of credit | $ 3,500,000 | $ 3,500,000
Senior Notes [Member] | Revolving Credit Facility [Member] | Minimum [Member] |  |
Debt Instrument [Line Items] |  |
Unused commitment fee | 0.075% |
Senior Notes [Member] | Revolving Credit Facility [Member] | Maximum [Member] |  |
Debt Instrument [Line Items] |  |
Unused commitment fee | 0.20% |
London Interbank Offered Rate (LIBOR) [Member] | Senior Notes [Member] | Revolving Credit Facility [Member] | Minimum [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Basis Spread on Variable Rate | 0.875% |
London Interbank Offered Rate (LIBOR) [Member] | Senior Notes [Member] | Revolving Credit Facility [Member] | Maximum [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Basis Spread on Variable Rate | 1.50% |

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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 Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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