v3.8.0.1

Segment Information (Details) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2017 USD ($) | Sep. 30, 2017 USD ($) | Jun. 30, 2017 USD ($) | Mar. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Sep. 30, 2016 USD ($) | Jun. 30, 2016 USD ($) | Mar. 31, 2016 USD ($) | Dec. 31, 2017 USD ($) segment | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Segment Reporting [Abstract] |  |  |  |  |  |  |  |  |  |  |
Number of Operating Segments | segment |  |  |  |  |  |  |  |  | 2 |  |
Revenues | $ 12,806 | $ 11,898 | $ 11,954 | $ 11,724 | $ 11,911 | $ 10,846 | $ 10,897 | $ 6,953 | $ 48,382 | $ 40,607 | $ 22,760
Earnings from operations |  |  |  |  |  |  |  |  | 1,199 | 1,260 | 705
Total assets | 21,855 |  |  |  | 20,197 |  |  |  | 21,855 | 20,197 | 7,339
Managed Care |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 45,798 | 38,182 | 20,865
Earnings from operations |  |  |  |  |  |  |  |  | 917 | 1,077 | 531
Total assets | 19,959 |  |  |  | 18,423 |  |  |  | 19,959 | 18,423 | 6,327
Specialty Services |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 2,584 | 2,425 | 1,895
Earnings from operations |  |  |  |  |  |  |  |  | 282 | 183 | 174
Total assets | $ 1,896 |  |  |  | $ 1,774 |  |  |  | 1,896 | 1,774 | 1,012
Operating Segments | Managed Care |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 45,842 | 38,382 | 20,966
Operating Segments | Specialty Services |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 12,055 | 8,377 | 6,757
Intersegment Eliminations |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | (9,515) | (6,152) | (4,963)
Intersegment Eliminations | Managed Care |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 44 | 200 | 101
Intersegment Eliminations | Specialty Services |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | $ 9,471 | $ 5,952 | $ 4,862

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- Definition Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues. + References No definition available. + Details
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