Condensed Consolidated Statements of Shareholders' Equity (Parentheticals) - USD ($) shares in Millions, $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2018		Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019
Treasury shares held in trust (in shares)	1	1		1	1	1	1
Treasury shares held in trust value	$ 29	$ 29		$ 29	$ 29	$ 29	$ 29
Common stock par value	17	17		17	17	17	17
Cumulative adjustment to retained earnings as a result of new accounting standard adoption	$ 68,355	$ 58,543		65,474	64,170	61,599	60,006
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201602Member
Retained Earnings
Cumulative adjustment to retained earnings as a result of new accounting standard adoption	$ 48,768	$ 40,911		$ 46,455	45,108	$ 43,136	$ 41,859
Cumulative Effect, Period of Adoption, Adjustment
Cumulative adjustment to retained earnings as a result of new accounting standard adoption		178	[1]		(3)
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings
Cumulative adjustment to retained earnings as a result of new accounting standard adoption		$ 178	[1]		$ (3)

[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.