Summary of Significant Accounting Policies Change In Accounting Principal (Details) $ in Millions |
Jan. 01, 2018
USD ($)
|
|---|---|
| Revenue, Initial Application Period Cumulative Effect Transition [Line Items] | |
| Cumulative Effect of New Accounting Principle in Period of Adoption | $ 14 |
| X | ||||||||||
- Definition Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption. No definition available.
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|