v3.19.1

Summary of Significant Accounting Policies Intangible Assets by Component (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Assets, Gross | $ 1,031 | $ 1,031 |
Finite-Lived Intangible Assets, Accumulated Amortization | 619 | 519 |
Finite-Lived Intangible Assets, Net | 412 | 512 |
Amortization of Intangible Assets | 100 | 175 | $ 218
Acquired contracts [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Assets, Gross | $ 458 | 458 |
Acquired contracts [Member] | Minimum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Asset, Useful Life | 0 years |  |
Acquired contracts [Member] | Maximum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Asset, Useful Life | 9 years |  |
Customer Relationships [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Assets, Gross | $ 445 | 445 |
Customer Relationships [Member] | Minimum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Asset, Useful Life | 7 years |  |
Customer Relationships [Member] | Maximum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Asset, Useful Life | 14 years |  |
Trademarks and Trade Names [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Assets, Gross | $ 40 | 40 |
Trademarks and Trade Names [Member] | Minimum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Asset, Useful Life | 15 years |  |
Trademarks and Trade Names [Member] | Maximum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Asset, Useful Life | 15 years |  |
Other Intangible Assets [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Assets, Gross | $ 88 | $ 88 |
Other Intangible Assets [Member] | Minimum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Asset, Useful Life | 17 years |  |
Other Intangible Assets [Member] | Maximum [Member] |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Finite-Lived Intangible Asset, Useful Life | 23 years |  |

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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274 + Details
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