Shareholders' Equity - Preferred Stock Narrative (Details) - USD ($)
$ in Millions
|3 Months Ended|
Mar. 31, 2019
Mar. 31, 2018
|Preferred stock dividends||$ 442||$ 428|
Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash.
Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef