Shareholders' Equity and Redeemable Non-controlling Interests, Shareholders' Equity, Components of accumulated other comprehensive income (loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), beginning of period	$ (1,784)	$ (1,363)
Other comprehensive income (loss) before reclassifications	(586)	(26)
Tax (expense) benefit before reclassifications	85	1
Amounts reclassified from accumulated other comprehensive income (loss)	(39)	(38)
Tax (expense) benefit	11	8
Net other comprehensive income (loss)	(529)	(55)
Accumulated other comprehensive income (loss), end of period	(2,313)	(1,418)
Financial derivatives [Member]
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), beginning of period	(200)	(68)
Other comprehensive income (loss) before reclassifications	(388)	(19)
Tax (expense) benefit before reclassifications	88	4
Amounts reclassified from accumulated other comprehensive income (loss)	(53)	(45)
Tax (expense) benefit	15	10
Net other comprehensive income (loss)	(338)	(50)
Accumulated other comprehensive income (loss), end of period	(538)	(118)
Unrealized gains (losses) on available-for-sale debt securities [Member]
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), beginning of period	0
Other comprehensive income (loss) before reclassifications	(3)
Tax (expense) benefit before reclassifications	1
Amounts reclassified from accumulated other comprehensive income (loss)	0
Tax (expense) benefit	0
Net other comprehensive income (loss)	(2)
Accumulated other comprehensive income (loss), end of period	(2)
Defined benefit pension and other postretirement benefit plans [Member]
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), beginning of period	(711)	(442)
Other comprehensive income (loss) before reclassifications	0	0
Tax (expense) benefit before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	14	7
Tax (expense) benefit	(4)	(2)
Net other comprehensive income (loss)	10	5
Accumulated other comprehensive income (loss), end of period	(701)	(437)
Foreign currency translation adjustments [Member]
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), beginning of period	(873)	(853)
Other comprehensive income (loss) before reclassifications	(195)	(7)
Tax (expense) benefit before reclassifications	(4)	(3)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Tax (expense) benefit	0	0
Net other comprehensive income (loss)	(199)	(10)
Accumulated other comprehensive income (loss), end of period	$ (1,072)	$ (863)