Goodwill and Other Intangible Assets - Summary of Changes in Goodwill Assets (Details) - USD ($)
$ in Millions |
12 Months Ended |
Dec. 31, 2019 |
Dec. 31, 2018 |
| Goodwill [Roll Forward] |
|
|
| Cost, beginning balance |
$ 4,068
|
$ 3,819
|
| Accumulated Impairment, beginning balance |
(2,493)
|
(2,440)
|
| Total Net, beginning balance |
1,575
|
1,379
|
| Goodwill from acquisitions |
3
|
249
|
| Goodwill impairment charge |
|
(53)
|
| Goodwill reduced through sale of Keystone operations |
(38)
|
|
| Less: Goodwill included in assets held for sale |
(39)
|
|
| Cost, ending balance |
3,941
|
4,068
|
| Accumulated Impairment, ending balance |
(2,440)
|
(2,493)
|
| Total Net, ending balance |
1,501
|
1,575
|
| Operating Segments |
|
|
| Goodwill [Roll Forward] |
|
|
| Goodwill impairment charge |
|
(53)
|
| Operating Segments | Regulated Businesses |
|
|
| Goodwill [Roll Forward] |
|
|
| Cost, beginning balance |
3,494
|
3,492
|
| Accumulated Impairment, beginning balance |
(2,332)
|
(2,332)
|
| Goodwill from acquisitions |
|
2
|
| Cost, ending balance |
3,458
|
3,494
|
| Accumulated Impairment, ending balance |
(2,332)
|
(2,332)
|
| Operating Segments | Market-Based Businesses |
|
|
| Goodwill [Roll Forward] |
|
|
| Cost, beginning balance |
574
|
327
|
| Accumulated Impairment, beginning balance |
(161)
|
(108)
|
| Goodwill from acquisitions |
|
247
|
| Cost, ending balance |
483
|
574
|
| Accumulated Impairment, ending balance |
(108)
|
$ (161)
|
| Regulated Water And Wastewater Systems | Regulated Businesses |
|
|
| Goodwill [Roll Forward] |
|
|
| Goodwill from acquisitions |
3
|
|
| Less: Goodwill included in assets held for sale |
(39)
|
|
| Keystone |
|
|
| Goodwill [Roll Forward] |
|
|
| Goodwill reduced through sale of Keystone operations |
(91)
|
|
| Goodwill reduced through sale of Keystone operations |
53
|
|
| Keystone | Operating Segments | Market-Based Businesses |
|
|
| Goodwill [Roll Forward] |
|
|
| Goodwill reduced through sale of Keystone operations |
(91)
|
|
| Goodwill reduced through sale of Keystone operations |
$ 53
|
|