Shareholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	6 Months Ended
	Jun. 22, 2020	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019
Class of Stock [Line Items]
Common stock dividends			$ 800
Dividends declared on preferred stock (Note 11)		$ 45
Amount set aside for dividend payments	$ 45
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Dividends declared on preferred stock (Note 11)	$ 29		29	$ 29
Preferred stock dividends paid (in dollars per share)	$ 28.75
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Dividends declared on preferred stock (Note 11)	$ 16		$ 16	$ 17
Preferred stock dividends paid (in dollars per share)	$ 32.50