Income taxes (Textual) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tax Credit Carryforward [Line Items]
Interest and penalties related to unrecognized tax benefits recognized in income tax provision	$ 198,000,000	$ 137,000,000	$ 56,000,000
Accrued interest and penalties associated with unrecognized tax benefits	667,000,000	469,000,000
Income taxes paid	1,900,000,000	$ 1,900,000,000	$ 1,500,000,000
Federal [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforwards available to reduce income taxes	20,000,000
Tax credit carryforwards, valuation allowance	0
NOL carryforwards available to reduce income taxes	144,000,000
NOL carryforwards, valuation allowance	6,000,000
Federal [Member] | Operating Losses That Expire Between 2020 and 2035 [Member]
Tax Credit Carryforward [Line Items]
NOL carryforwards, valuation allowance	0
State [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforwards available to reduce income taxes	605,000,000
Tax credit carryforwards, valuation allowance	482,000,000
NOL carryforwards available to reduce income taxes	196,000,000
NOL carryforwards, valuation allowance	196,000,000
State [Member] | Expiration in tax years beginning 2022 [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforwards, valuation allowance	0
Foreign [Member]
Tax Credit Carryforward [Line Items]
NOL carryforwards available to reduce income taxes	2,000,000,000.0
NOL carryforwards, valuation allowance	516,000,000
NOLs with no valuation allowance and no expiration	822,000,000
Foreign [Member] | Operating Losses That Expire Between 2020 and 2024 [Member]
Tax Credit Carryforward [Line Items]
NOL carryforwards, valuation allowance	$ 0