Condensed Consolidated Statements of Shareholders' Equity (Parentheticals) - USD ($) shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Treasury shares held in trust (in shares)	1				1
Treasury Stock, Value, Shares Held In Trust	$ 29	$ 29	$ 29		$ 29	$ 29	$ 29	$ 29
Common Stock, Value, Issued	17	17	17	$ 17	17	17	17	17
Cumulative adjustment to retained earnings as a result of new accounting standard adoption	$ 69,112	68,355	65,474	64,170	62,933	61,599	60,006	58,543
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Retained Earnings
Cumulative adjustment to retained earnings as a result of new accounting standard adoption	$ 49,328	$ 48,768	$ 46,455	45,108	$ 44,017	$ 43,136	$ 41,859	40,911
Cumulative Effect, Period of Adoption, Adjustment
Cumulative adjustment to retained earnings as a result of new accounting standard adoption				(3)				178	[1]
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings
Cumulative adjustment to retained earnings as a result of new accounting standard adoption				$ (3)				$ 178	[1]

[1] Reflects the adoption of Accounting Standards Update (“ASU”) 2016-02, Leases (Topic 842), which resulted in an increase to retained earnings of $178 million during the three months ended March 31, 2019.