Employee Benefit Plans - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2019
Compensation and Retirement Disclosure [Abstract]
Number of days used to compute performance period average closing price of restricted stock units		20 days
RSUs
Compensation and Retirement Disclosure [Abstract]
Awards granted (in shares)		1.1
Vesting period		3 years
Time-Vested RSUs
Compensation and Retirement Disclosure [Abstract]
Awards granted (in shares)		0.8
Performance-Based RSUs
Compensation and Retirement Disclosure [Abstract]
Awards granted (in shares)		0.3
Pension Benefits
Compensation and Retirement Disclosure [Abstract]
Employer contribution to tax-qualified defined benefit pension plans	$ 150	$ 300

The time period over which the stock closing prices are averaged to arrive at a per-share valuation for equity based awards such as Restricted Stock Units, Performance Share and other equity based awards.

No definition available.

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- References

No definition available.

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- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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