Summary of effects of initial adoption of ASU 2016-01, ASU 2018-02 and ASC 606 (Detail) - USD ($)
$ in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Assets |
$ 707,794
|
$ 702,095
|
$ 620,854
|
|
| Liabilities |
355,294
|
350,141
|
|
|
| Accumulated other comprehensive income |
(5,015)
|
58,571
|
|
|
| Retained earnings |
321,112
|
255,786
|
|
|
| Total shareholders' equity |
352,500
|
$ 351,954
|
$ 285,428
|
$ 257,696
|
| ASU 2018-02 [Member] |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Accumulated other comprehensive income |
84
|
|
|
|
| Retained earnings |
(84)
|
|
|
|
| ASC 606 [Member] |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Assets |
3,382
|
|
|
|
| Liabilities |
3,453
|
|
|
|
| Retained earnings |
(70)
|
|
|
|
| Total shareholders' equity |
(70)
|
|
|
|
| ASU 2016-01 [Member] |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Accumulated other comprehensive income |
(61,459)
|
|
|
|
| Retained earnings |
61,459
|
|
|
|
| Adjustments for New Accounting Pronouncements [Member] |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Assets |
3,382
|
|
|
|
| Liabilities |
3,453
|
|
|
|
| Accumulated other comprehensive income |
(61,375)
|
|
|
|
| Retained earnings |
61,305
|
|
|
|
| Total shareholders' equity |
$ (70)
|
|
|
|