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Debt (Schedule Of Outstanding Debt) (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 | Mar. 31, 2016
--- | --- | --- | ---
Debt Instrument [Line Items] |  |  |
Commercial paper outstanding | $ 0 | $ 50 |
Current portion of long-term debt | 262 | 262 |
Short-term debt | 262 | 312 |
Long-term debt, current and noncurrent | 5,487 | 4,757 |
Long-term debt and capital lease obligations | 5,225 | 4,495 |
2.30% Senior Debt Obligations Due 2017 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 0 | 250 |
Interest rate | 2.30% |  |
2.55% Senior Debt Obligations Due 2018 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 250 | 249 |
Interest rate | 2.55% |  |
2.35% Senior Debt Obligations Due 2019 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 299 | 299 |
Interest rate | 2.35% |  |
2.35% Senior Debt Obligations Due 2020 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 498 | 497 |
Interest rate | 2.35% |  |
4.80% Senior Debt Obligations Due 2021 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 498 | 498 |
Interest rate | 4.80% |  |
2.75% Senior Debt Obligations Due 2022 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 496 | 0 |
Interest rate | 2.75% |  |
3.30% Senior Debt Obligations Due 2023 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 348 | 347 |
Interest rate | 3.30% |  | 3.30%
4.05% Senior Debt Obligations Due 2023 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 248 | 248 |
Interest rate | 4.05% |  |
3.50% Senior Debt Obligations Due 2024 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 596 | 596 |
Interest rate | 3.50% |  |
3.50% Senior Debt Obligations Due 2025 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 496 | 495 |
Interest rate | 3.50% |  |
3.75% Senior Debt Obligations Due 2026 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 596 | 596 |
Interest rate | 3.75% |  |
5.875% Senior Debt Obligations Due 2033 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 297 | 297 |
Interest rate | 5.875% |  |
4.35% Senior Debt Obligation Due 2047 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 492 | 0 |
Interest rate | 4.35% |  |
Mortgage Due 2035 |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 370 | 382 |
Interest rate | 5.70% |  |
Other Debt Instruments |  |  |
Debt Instrument [Line Items] |  |  |
Long-term debt, current and noncurrent | $ 3 | $ 3 |

X
- Definition Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(a)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -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=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)(2)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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