Goodwill and Other Intangible Assets (Intangible Assets Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired during the year	$ 0
Finite-lived intangible assets, gross	1,000,000		$ 1,000,000
Net, intangible asset not subject to amortization	60,000,000		63,000,000
Gross carrying amount of capitalized software	1,100,000,000		1,100,000,000
Capitalized computer software, net	301,000,000		321,000,000
Capitalized computer software, development stage costs	39,000,000
Capitalized Internal Use Software [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible asset, residual value	0
Amortization expense	32,000,000	$ 30,000,000
Amortization expense for remainder 2020	94,000,000
Amortization expense for 2021	108,000,000
Amortization expense for 2022	52,000,000
Amortization expense for 2023	24,000,000
Amortization expense for 2024	12,000,000
Amortization expense for 2025	6,000,000
Amortization expense thereafter	$ 5,000,000
Capitalized Internal Use Software, Except Significant System Conversions [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average amortization period	3 years
Minimum [Member] | Capitalized Internal Use Software, Significant System Conversions [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average amortization period	8 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived intangible assets, net	$ 1,000,000		$ 1,000,000
Maximum [Member] | Capitalized Internal Use Software, Significant System Conversions [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average amortization period	10 years