Equity - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Dec. 31, 2017	Jul. 02, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		$ 14,280	$ 34,876	$ 38,396	$ 14,280
Other comprehensive loss before reclassifications			(54)	(579)
Amounts reclassified from accumulated other comprehensive loss			(27)	(6)
Deferred taxes			(19)	0
Other comprehensive income (loss)	$ 123	(66)	(8)	(573)	57
Less: Other comprehensive loss attributable to noncontrolling interests			0	0	3
Less: Other adjustments			119	8
Ending balance	38,396		34,414	34,876	38,396
Investment Securities, Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			0	3
Ending balance	3		2	0	3
Investment Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive loss before reclassifications			2	(1)
Amounts reclassified from accumulated other comprehensive loss			0	0
Deferred taxes			0	2
Other comprehensive income (loss)			2	(3)
Investment Securities, Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Less: Other comprehensive loss attributable to noncontrolling interests				0
Less: Other adjustments			0
Foreign Currency Translation Adjustment, Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			(2,327)	(1,825)
Ending balance	(1,825)		(2,274)	(2,327)	(1,825)
Foreign Currency Translation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive loss before reclassifications			53	(502)
Amounts reclassified from accumulated other comprehensive loss			0	0
Deferred taxes			0	0
Other comprehensive income (loss)			53	(502)
Foreign Currency Translation Adjustment, Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Less: Other comprehensive loss attributable to noncontrolling interests				0
Less: Other adjustments			0
Cash Flow Hedges, Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			(2)	2
Ending balance	2		10	(2)	2
Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive loss before reclassifications			13	(6)
Amounts reclassified from accumulated other comprehensive loss			(1)	(1)
Deferred taxes			2	(1)
Other comprehensive income (loss)			12	(4)
Cash Flow Hedges, Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Less: Other comprehensive loss attributable to noncontrolling interests				0
Less: Other adjustments			0
Benefit Plans, Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			(133)	(61)
Ending balance	(61)		(327)	(133)	(61)
Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Other comprehensive loss before reclassifications			(122)	(70)
Amounts reclassified from accumulated other comprehensive loss			(26)	(5)
Deferred taxes			(21)	(1)
Other comprehensive income (loss)			(75)	(64)
Benefit Plans, Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Less: Other comprehensive loss attributable to noncontrolling interests				8
Less: Other adjustments			119
Accumulated Other Comprehensive Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(1,888)	(2,462)	(1,881)	(1,888)
Other comprehensive income (loss)	123	$ (69)	(8)	(573)
Ending balance	$ (1,881)		$ (2,589)	$ (2,462)	$ (1,881)